The old adage about the tight-head prop being the most important player in the side plays out across the Super Rugby semi-finals this weekend.
Of the four sides left, three have the starting tight-heads for the Wallabies (Sekope Kepu), All Blacks (Owen Franks) and Springboks (Jannie du Plessis) respectively, and the other No.3 (Ben Alexander) is the second choice for his country.
In no other position across the semi-finalists is there such a concentration of first-choice Test players.
But even the big men will concede the No.10 has a bit to do with the game plan as well, and the performance of the Brumbies' Matt Toomua against the Chiefs last week will have been looked at closely by the Waratahs.
Toomua is an unusual No.10 because of the way he defends. On three occasions last week, he either helped shut down a play or actually intercepted a Chiefs pass from the base of a ruck due to his willingness to rocket forward out of the defensive line.
But it's a high-wire act. He was caught out badly for the Chiefs' fourth try, which could have been very costly, and while his line speed and hard tackling can rattle opponents, the Waratahs will be happy if he keeps doing it on on Saturday night.
Toomua has drawn comparisons to Jonny Wilkinson or Dan Carter for his defensive prowess, but those are probably a bit premature. He's certainly a great tackler, which often makes him a great defender, but not always. Carter, for example, is the master of the drift defence – sometimes he won't even need to make much contact to do his job, he'll just push the ball carrier towards the sideline and crowd the space for the winger.
In some ways, Toomua is more like former Springbok Butch James – but legal – or even De Wet Barry, the ferocious No.12 who built his game around line speed and intimidation.
When he gets it right, it's impressive. As mentioned above, in the 32nd minute, 54th minute and 73rd minute last week Toomua made vital contributions by coming up quick and stopping the Chiefs' attack. There will always be question marks about offside when a player repeatedly does this, but Toomua is pretty clever. On occasion he sets himself like a sprinter on the blocks, so his feet are well back. Referee Craig Joubert is a good communicator with his assistant refs on the sideline and saw no problem, so Toomua does it well.
But, as always, there's a but. When the Chiefs set a good scrum in the 49th minute and halfback Tawera Kerr-Barlow simply picked up quick ball and ran straight and hard – denying Toomua the chance to line someone up, he burst over the advantage line through Toomua's inside shoulder. A try was scored a few phases later.
And when you look at what was different about the Chiefs' success with that play as opposed to the ones when Toomua shut them down, it simply comes down to the quality and speed of ball. When the Chiefs had a laboured delivery from the base, from loose-head prop Jamie Mackintosh, hooker Mahonri Schwalger, or a no-look pass from Bundee Aki, Toomua profited. When the Chiefs had accurate ball – different story.
This was the case again again in the 76th minute when the Chiefs had a scrum close to the Brumbies line and Toomua shot up to put a massive hit on replacement halfback Augustine Pulu and missed him, again on the inside shoulder, which created the room for the Chiefs to go over for a try that could have tied the scores but for Aaron Cruden's failed conversion. The line Toomua takes when he does this is so unforgiving for a defender – it's square, almost outside to in, and there's no safety net when he misses.
Which brings us back to our old mate the tight-head prop. In both the scrums that led to the Chiefs' tries, No.3 Ben Tameifuna did his job. Even though the second wasn't overly stable, any lateral movement suited the Chiefs – it opened up the side of the field they wanted to attack. The Waratahs are a pretty complete team. They can beat the Brumbies a number of ways – but if Kepu and Paddy Ryan get it right at the scrum they have the threats in No.9, No.10. No.12 and No.15 that can flip what can be a particular Brumbies strength into a weakness.