Wallabies make it three straight but 'ruthless streak' still a work in progress

Are the Wallabies finally building some depth? (2:42)

Sam Bruce and Christy Doran discuss Dave Rennie's considered expansion of the Wallabies squad and how it has led to an increase in depth. (2:42)

Job done.

The Wallabies managed to string a third successive Rugby Championship win together for the first time in six years on Saturday night in Townsville, but they were unable to find the "ruthless edge" skipper Michael Hooper was after to put away the Pumas.

Australia's 27-8 win was comfortable enough in the end. But had it not been for two ridiculously idiotic plays from Pumas lock Marcos Kremer the second half script -- and potentially the match -- could have been flipped on its head.

With his team enjoying the second-half ascendancy, Kremer twice had Argentine penalties overturned for dangerous play, his second offense -- a trip on Wallabies fullback Reece Hodge -- enough for the flanker to rightfully be sent to the sin-bin.

As it was, the Pumas only allowed Australia a penalty while Kremer was off. But the visitors had five-metre lineout drives that were well defended while down to 14 men; they would have been just that little bit more effective had the No. 7 been on the paddock.

Australia were as a result forced to scrap their way to the final whistle having earlier enjoyed the lion's share of momentum, territory and possession in the first half.

"We're obviously happy to win, we worked really hard in the first half to put ourselves in a strong position," Wallabies coach Dave Rennie said. "And probably a bit of frustration from us that we had a lot of opportunities late to put them out of the game and didn't do the obvious, we've just got to throw one more pass.

"So there's a bit of frustration around that, but we worked hard, we had to sustain a lot of pressure in the 20 minutes after halftime, so I guess mixed emotions.

"Happy to win but we need to be better."

When Reece Hodge and Samu Kerevi crossed within the opening quarter, it looked like the Wallabies were on their way to a comfortable win.

But they were unable to land the third try of the first half that would have really left the Pumas with their heads down at the break. One player who won't love the finish of the first-half video session will be Wallabies No. 9 Nic White who, with Australia hard on the attack, placed the ball down against the post pad.

The only issue? The law that used to see such a grounding good enough for a try was removed in May last year.

"Absolutely I did, he is an absolute rugby nerd and then goes and places it at the post, that rule's been there for two years," Hooper quipped when asked if he'd given White a spray as the television pictures had appeared to indicate.

"I think I did it last year as well, so I can't really give him too much crap. But he'll definitely be kicking himself."

White will surely come in for some gentle ribbing from his teammates through the week, but his lack of familiarity with World Rugby's lawbook was almost emblematic of Australia's effort in Townsville, particularly late in the match when they pressed for what would have been the bonus-point try.

While Andrew Kellaway finally got Australia over the line 10 minutes from the final siren, Australia twice squandered golden opportunities thereafter. Perhaps some of that could be put down to the sweaty conditions, the swag of replacements, including James O'Connor, that were introduced, and then just the general weariness of what has now been four Tests in four weeks.

But if Australia are really to take that next step up under Rennie, it is the ruthless edge that Hooper spoke of pre-match that they simply must develop.

Samu Kerevi, again, was dominant. The Fijian-born centre provided the thrust for the Wallabies attack throughout, his early charge giving Australia the field position that allowed Hodge to show his strength and footwork for the Test's opening try.

Kerevi again demonstrated his power by scrambling the ball down next to the posts, after a wonderful grubber kick from Quade Cooper and a determined chase by Len Ikitau, who looks better with every game in the jersey.

Cooper, too, was among the Wallabies' top performers, the newfound maturity in his game evident in not only the grubber for Ikitau, but then too his ability to find space up the middle of the paddock when coming out of his own half.

Kellaway, meanwhile, continues to impress on the right wing and is fast becoming the Wallabies' find of the season. The Rebels utility makes a lot of excellent decisions, whether it be to take the ball to the deck when half-tackled or to hunt back in field when short on space; he is more often than not getting those micro-calls right.

Up front, the Wallabies had their issues at both the scrum and lineout but again received good shifts from Taniela Tupou and Rob Valetini. Rob Leota, making his first Test start, was solid at No. 6 but Rennie indicated after the match that Sean McMahon could "potentially" feature next week.

McMahon's selection would be welcomed by many, as Australia still appear to be that one true damaging ball-carrier short in the pack.

While the Pumas will lament Kremer's separate brain explosions, they will also count Emiliano Boffelli's wayward kicking as costly after the fullback left eight points out on the paddock inside 50 minutes. Had Boffelli slotted each of those three missed kicks, the Pumas would have trailed by just one nearing the match's final quarter and the Wallabies may well have become the 'Wobblebies'.

"I just think that the first couple of tries were pretty easy for them, they didn't have to work a lot for them," Pumas coach Mario Ledesma said. "And then we started coming back, at one point we're 17-8 [down] and at that point we missed eight points with the kicking, and it's difficult when you're running after the score while you're not scoring."

Australia can now set their sights on finding the clinical edge in both their execution and finishing in their tournament finale, against the same opposition, next week.

Crucially, they have retained the momentum they worked so hard for against South Africa.

Clearly there are tougher Tests on the horizon up north come November, but having moved to a 5-4 record for the year, and a winning season now there for the taking, it is the ability to put teams away that Australia must now master.