Champions League talking points: End of the road for Liverpool? Wake-up call for Premier League?

Why Napoli are a 'nightmare matchup' for anyone in the UCL (1:53)

The ESPN FC crew speak about Napoli's Champions League credentials after their 2-0 win over Frankfurt. (1:53)

The first legs of this season's Champions League round of 16 were a chastening set of results for the Premier League clubs as a whole and Liverpool in particular. Jurgen Klopp's side were humbled at home by Real Madrid while none of Chelsea, Manchester City or Tottenham Hotspur are ahead at the halfway stage of their ties.

Paris Saint-Germain also have to come from behind if they are to progress at the expense of Bayern Munich, but a brief appearance from a half-fit Kylian Mbappe is enough to give them hope.

Our writers Mark Ogden, Julien Laurens and Rob Dawson 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 first legs?

Ogden: Liverpool have been Champions League heavyweights for five years -- playing in three finals and winning one of them -- but their 5-2 defeat at home to Real Madrid on Tuesday looked like the end of the road for many of Jurgen Klopp's team.

Jordan Henderson, Trent Alexander-Arnold, Fabinho and Joe Gomez all looked well past their best as Real put on a masterclass at Anfield. Henderson no longer has the legs to get around the pitch and cope with the talent that Real have in abundance, while Alexander-Arnold and Gomez have become liabilities in defence. Fabinho, meanwhile, cannot control the game from his defensive midfield position like he used to. Not so long ago, Liverpool dominated opponents with their breathtaking attacking ability and rock-solid defence, but their game plan has now been exposed by the failings of previously key players. Even Virgil van Dijk is looking like a player with his best days behind him.

Judging by their first-leg deficit and battle to climb into the Premier League top four, Liverpool might not even be in the Champions League next season, so the rebuilding project may have to start in the Europa League -- and that kind of future is unlikely to appeal to top targets such as Borussia Dortmund's Jude Bellingham.

Dawson: There is no obvious winner of the Champions League this year. Not only is the draw going to open when Liverpool and one of Bayern Munich or Paris Saint-Germain go out, but established favourites like Manchester City showed they can be vulnerable. City certainly have work to do against RB Leipzig in Manchester after drawing the first leg 1-1 in Germany.

Real Madrid's win at Anfield was the most impressive performance of the round so far but even they were 2-0 down early on against a Liverpool side having a disastrous season. City, Real Madrid, Bayern and PSG will all believe they can lift the trophy in Istanbul, but so will Napoli, Internazionale and Chelsea. That's at least seven teams with a genuine hope of winning it which should make for some exciting second legs in the round of 16 and a thrilling set of quarterfinals once the draw is made.

Laurens: Four English clubs, zero wins. For all the talk of English domination and Premier League supremacy, mostly because of their financial power, the first legs of the round of 16 are a reminder that the rest of Europe is still pretty competitive. The results are also a bit of a wake-up call because Liverpool, Manchester City, Chelsea and Tottenham Hotspur have no margin for error in their ties.

Maybe the top English clubs got too cocky, but it has been a pretty disastrous couple of weeks. Liverpool were destroyed by Real Madrid, Tottenham were not good enough in Milan, Chelsea were beaten by a wonder goal and Manchester City fell asleep after an hour. Of course, they all can still qualify (sorry, Liverpool fans, but not you) but even if coaches Pep Guardiola, Antonio Conte, Graham Potter and their players do go through after the second legs where they will play at home, the perception of English superiority will have changed. They are not unbeatable; they are not miles better than the rest; it won't automatically be a whole English last four; you can get to them. But these four clubs will also want to show pride to go through. The return fixtures will be fascinating.

Which team that's behind in their tie has the best chance of progressing?

Dawson: Chelsea are on an awful run under Graham Potter but they did enough during the 1-0 defeat at Borussia Dortmund to suggest they are more than capable of turning the tie around at Stamford Bridge. Whether they will is another matter. Chelsea had 21 shots and eight on target in Germany but were eventually beaten by a wonderful solo goal from Karim Adeyemi. Play in the same way back in London and Potter can look forward to a quarterfinal, and from there, who knows?

Chelsea certainly have the players to frighten the favourites, if not the form or the confidence. Form is a massive problem and Potter, only a few months on from replacing Thomas Tuchel, is already under pressure -- from fans if not yet the owners. Four wins from 19 games is not a run of results which suggests they can go deep in the Champions League this season, but there were signs of life in defeat at Dortmund and the home leg is a chance to trigger an upturn in fortunes.

Ogden: Tottenham were lucky to return from San Siro with just a 1-0 first-leg deficit against AC Milan after conceding so many chances against the Italian champions. But having kept Milan's lead to one goal, Spurs should be able to find the goals to turn the tie around in their favour in the second leg.

It is perhaps the closest of all of the eight round-of-16 ties in terms of the strength and quality of both teams. Neither will win this season's Champions League and the quarterfinals will probably be the end of the road for whichever side goes through. But even though Tottenham's home record at their new stadium is patchy in the Champions League -- Bayern Munich, Ajax Amsterdam and RB Leipzig have all recorded easy wins at Spurs -- Conte's side should make it through.

Laurens: Paris Saint-Germain. For one simple reason: they have Kylian Mbappe. The Paris prodigy only came on as a sub in the 1-0 defeat at Bayern Munich but his 30-minute cameo changed the whole dynamic of the game. He sent the Munich players into complete panic mode, created chances and almost scored. In two weeks at the Allianz Arena, he will be there from the start of the match.

Mbappe is probably PSG's only hope, but boy is he a good one. If there is one player capable of turning this tie around and knocking out Bayern in their own backyard, it's him. Straight after the end of the first leg, he started galvanising his teammates for the second leg, insisting that qualification was possible. Mbappe will be on a mission in the second leg and that's a scary thought for Bayern.

After Liverpool's 5-2 humbling at Anfield by Real Madrid, what's the most stunning Champions League result that you've witnessed live?

Laurens: Nothing will ever beat the 2005 final between Liverpool and AC Milan. There have been great remontadas, amazing twists and wonderful comebacks in the past few years of course. But in Istanbul 18 years ago, something surreal actually happened, some sort of magic which made Milan go from world-beaters to scared of their own shadow and made Liverpool play like if their lives depended on the final result.

I've never seen an atmosphere like that, where each half of the stadium goes through every possible emotion. I've never seen a collapse of the magnitude of the one Milan suffered that night. From 3-0 up to 3-3, the big chances missed in extra time when Liverpool were on the ropes again, and finally the penalty shootout. It was unbelievable. I can guarantee you already that nothing will ever surpass Istanbul 2005.

Ogden: Nobody who was at Liverpool's 4-0 win against Barcelona at Anfield in the 2018-19 semifinal second leg will be able to claim they attended a more incredible, dramatic and unforgettable game. Monaco's 5-3 round-of-16 first-leg defeat at Manchester City in 2017 was stunning in different ways -- Radamel Falcao and a teenage Mbappe tore City's defence apart to tee up a second-leg win which took the French team through on away goals, but while that game was remarkable, it can't top Liverpool's rout of Barcelona.

Anfield on a European night is special. The Liverpool players are transformed by the atmosphere and opponents can be overrun, as Barca were that night. The abiding memory is of the Liverpool fans turning on former hero Luis Suarez, who was by now playing for Barcelona. Suarez was loved at Anfield, but with Champions League glory at stake even he was taunted by the hostile crowd, who played their part in a historic Liverpool victory.

Dawson: The 2011 Champions League final wasn't shocking because of the result, but because of the way Barcelona completely dismantled a Manchester United side who were playing in their third final in four years. Sir Alex Ferguson's team had established themselves as one of the dominant forces in Europe, but at Wembley they were swept aside by Pep Guardiola's Barcelona who treated the game like a training session for most of the second half.

The most memorable part of the game was the half-time break. Somehow, after Wayne Rooney's equaliser that had arrived out of nothing, United went in at the interval with the score at 1-1. Anyone checking the scoreline would have thought that United were well in the game but the thousands of fans who had come from Manchester were almost silent at half-time. It was like they knew what was coming, and they were right. Barcelona cantered to a 3-1 victory as United barely touched the ball during the second half.

Finally, pick your eight quarterfinalists!

Ogden: Tottenham, Dortmund, Bayern Munich, Benfica, Real Madrid, Napoli, Porto, Manchester City.

Dawson: Bayern, Chelsea, Tottenham, Manchester City, Porto, Benfica, Napoli, Real Madrid.

Laurens: Tottenham, Chelsea, PSG, Benfica, Real Madrid, Napoli, Inter, Manchester City.