Champions League talking points: Does five-goal Haaland make Man City favourites? Is VAR getting worse?

This season's Champions League round of 16 is done and dusted with some European heavyweights falling by the wayside like Liverpool, who have reached three finals in the last five years, and a Paris Saint-Germain side featuring Kylian Mbappe and Lionel Messi.

Friday's quarterfinal draw will feature plenty of European heavyweights such as defending champions Real Madrid and recent winners Chelsea and Bayern Munich. Reigning Premier League champions Manchester City are also in the hat along with Portuguese side Benfica, while Serie A has three clubs in the last eight: AC Milan, Inter Milan and Napoli.

Our writers Mark Ogden, Julien Laurens and James Olley answer some of the big questions arising from this round of games.

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What caught your eye from the round-of-16 second legs?

Ogden: The poor standard of refereeing, and VAR, has really stood out during the round of 16, and it is even more noticeable because the Champions League generally operates to a much higher level than the domestic leagues in Europe. Two English teams, Chelsea and Manchester City, have been the biggest beneficiaries of some bewildering decisions, with German sides Borussia Dortmund and RB Leipzig on the wrong end of them.

Chelsea were fortunate to be awarded a penalty during their 2-0 second-leg win against Dortmund when defender Marius Wolf was judged to have handled the ball. Referee Danny Makkelie didn't point to the spot until the VAR suggested a review on the pitchside monitor. Wolf was so close to the ball that he couldn't move out of the way, but Makkelie awarded the penalty when he should have dismissed the VAR review.

Leipzig suffered an even heavier blow during their 7-0 defeat at City. VAR once again intervened in a penalty incident, calling on referee Slavko Vincic to review an apparent handball by Benjamin Henrichs. The reality was that Henrichs had his back to Rodri, whose header brushed his arm and fell to a City player without deviating in movement. It was incredibly soft, but once the penalty was awarded, Erling Haaland put City 1-0 ahead. Moments later, Timo Werner was booked, despite being on the receiving end of a foul by Ederson which could have resulted in a red card for the City goalkeeper. Yet VAR did not intervene. Two huge decisions which, had they gone Leipzig's way, could have resulted in a much different outcome.

VAR and the referees have to be better in the quarterfinals and beyond.

Laurens: It is probably the most obvious answer (and, I promise, I tried to find something else to be more original) but nothing can beat Haaland's quintuple against RB Leipzig. He might have got six goals had he stayed longer on the pitch, but Pep Guardiola took him off after 63 minutes.

The Manchester City striker became only the third man in Champions League history to score five goals in the same game, after Messi and Luiz Adriano, and by becoming the youngest-ever player to reach 30 Champions League goals. For his club, he is now the top scorer in a single season with 39 goals, beating the old record of Tommy Johnson from 1929. Haaland still has as many as 19 more games to play before the end of the season.

It is still an amazing achievement; Haaland had eight shots on the night, all on target, scored five goals with an xG (Expected Goals) of less than three. He was so aggressive in the box, so alert, so on it. He looked possessed at times. It was just incredible.

Olley: If Graham Potter makes a success of his time at Chelsea, he may well look back on their second leg win over Dortmund as the turning point. Managers often talk about uniting the fans and making their home stadium a difficult place for visiting teams, but in Potter's case he did so in the knowledge this game served as something of a referendum on his management.

An unconvincing win over Leeds United a few days earlier had at created a modicum of momentum heading into the game but, make no mistake, defeat against Dortmund would have ramped up the pressure on Potter. Dortmund were depleted -- Karim Adeyemi, Youssoufa Moukoko and goalkeeper Gregor Kobel all missed out injured while Julian Brandt was forced off after just five minutes -- but Chelsea produced a committed and defiant display, overcoming their goal-scoring problems to overturn a 1-0 first-leg deficit with a 2-0 win at Stamford Bridge.

The players showed they were behind Potter and although it will be some time before the majority of the fans are convinced the former Brighton & Hove Albion boss is the right man to lead them back to former glories, this win buys him time with a Champions League quarterfinal as proof of progress. They surely aren't good enough to lift the trophy in Istanbul, but, then again, most people felt that way before they won in 2012 and 2021...

Now the quarterfinalists are all set; which team is your favourite to lift the trophy in Istanbul?

Laurens: Pep Guardiola can be as sarcastic as he wants about the Champions League and what a failure he is and will always be, even if he wins the competition for the next three years. He can talk about Julia Roberts, Richard Gere or any Hollywood actor as much as he wants. His team are once again the big favourites of this Champions League, and not winning it would be a failure -- again.

City have everything, really: the manager, the squad depth, the superstars, the clutch players, the winning mentality, the experience of going far and the motivation of not yet winning it. They should have won it already and they will surely eventually do so. This year is their year. The rest of the field is not at their level, not even Bayern Munich, Napoli or Real Madrid.

Time is running out for Kevin De Bruyne, who turns 32 in June. Riyad Mahrez and Kyle Walker are already at that age, while Ikay Gundogan is out of contract this summer. Bernardo Silva could be leaving at the end of the season, too, a year after pushing for a departure.

The most important thing is that surely Pep and City have learned from their past mistakes in the Champions League: the 2021 final loss, the semifinal of last season and all the previous quarterfinal disappointments. If they can do that, they will finally be ready to achieve their ultimate aim.

Ogden: This may be a case of heart overruling head, but Napoli have been the most exciting team in this season's Champions League and it would be great for the game if Luciano Spalletti can take the club all the way to glory in Istanbul.

They certainly have the players, and it's not just about top scorer Victor Osimhen. Kim Min-Jae, Piotr Zielinski, Hirving "Chucky" Lozano and Giovanni Simeone have all had outstanding seasons, while Khvicha Kvaratskhelia has arguably been the breakthrough star of the 2022-23 Champions League.

The big challenge for Napoli, who are nailed on to win Serie A this season for the first time since 1990, is to hold their nerve and play their own game against a European superpower such as Real Madrid or Bayern Munich. If they stick to what has served them so well, Napoli can beat anybody, but the top clubs usually find a way to win the Champions League.

We haven't seen a surprise team win the competition since Jose Mourinho's FC Porto in 2004, so maybe this is Napoli's time.

Olley: It should, in all probability, be Manchester City but I can't say that a team clearly stands out from the rest at this stage. Mark makes a compelling case for Napoli -- and an 18-point lead at the top of Serie A gives them the chance to do what other clubs can't, which is rest players in the league to keep everyone fully fresh for the latter stages of the Champions League.

City have been knocking on the door for years but, even though they thrashed Leipzig in midweek, they have not been anything like their fluid best for much of the season. The jury is out as to whether this Bayern Munich is as strong as previous incarnations -- although we must all take note when club legend Lothar Matthaus says this group may be their best-ever squad.

And then we come to the team that mask their own weaknesses and exploit others better than anyone else: Real Madrid. With little conviction, given Napoli's form, City's individuals and Bayern's pedigree, perhaps Real's knowhow can help Carlo Ancelotti trump his rivals once more.

After Haaland's five-goal haul, what's the most impressive individual performance you've seen live in the Champions League?

Olley: Messi scoring all four as Barcelona beat Arsenal 4-1 at Camp Nou in April 2010. Maybe the Gunners made the mistake of taking the lead. At that stage, Arsenal led this quarterfinal tie 4-2 on aggregate but what came next was a true force of nature. Messi took it upon himself to deliver the kind of virtuoso performance that epitomises his glittering career.

The first goal was a fierce drive as the ball fell to him on the edge of the box, the second a close-range finish lifted over Manuel Almunia. His hat-trick goal was sublime; sent racing clear, he scooped a left-footed shot over the onrushing Almunia with embarrassing ease, prompting that worshipping celebration from an awe-struck Barcelona crowd. The fourth came with a drop of the shoulder, panicking defenders contorting themselves in ever more desperate shapes, and a shot saved by Almunia but drilled through his legs on the rebound. This was a high-pressure occasion but here was a 22-year-old making the game look so breathtakingly, devastatingly simple. Perhaps Wenger put it best: "He made the impossible possible."

The image that lingers in my mind came just after the final whistle. Messi was given the match ball and as Arsenal's players looked crestfallen, Barca supporters stood in disbelief, the little magician at the centre of it all simply spun the ball in his hand wearing a beaming smile, so fresh-faced he looked ready immediately to do it all over again.

Ogden: I was at the Santiago Bernabeu in 2017 when Cristiano Ronaldo scored a hat trick to give Real Madrid a 3-0 semifinal first-leg win against Atletico Madrid, but it was about more than merely scoring three goals, which he has achieved an incredible 62 times so far in his career.

It may seem unlikely now, six years on, but at the time the game was billed as a clash between Ronaldo and Atleti's rising star Antoine Griezmann, who was enjoying an outstanding season for Diego Simeone's team. There was genuine belief that Atleti could avenge the Champions League final defeats of 2014 and 2016 against their city rivals, with the France forward inspiring them to the final and outshining Ronaldo in the process.

But Ronaldo was having none of that. It seemed as though he was given extra motivation to prove he was still the king of Madrid and he dominated the game. He also recorded two landmarks by netting his 50th goal in the Champions League knockout stages and equalling Messi's record of seven hat tricks in the competition.

Laurens: I could pick any moment from Karim Benzema in the knockout phase last season; I was there for all of it. I had never witnessed anything like it before. He scored 10 goals in the six games that he and Real Madrid played on their way to the final at the Stade de France. You have seen players be on fire over one game or two, maybe three, but never six in a row!

The most impressive was maybe his 17-minute hat trick against PSG in the round-of-16 second leg, because Real Madrid looked doomed after losing the first leg 1-0 in Paris and being a further goal down at half-time at the Bernabeu. Going past the Parisians, in an incredible atmosphere, set the tone for the rest of the competition. There was nothing stopping Benzema and Real Madrid after that, as we saw against Chelsea (three goals away and one at home) and Manchester City (two goals away and one at home).

To see a player of Benzema's status perform miracles like he did last season in these games in person was incredible. Witnessing greatness like that was very special indeed.