The New Zealand-born centre has hit punishing new heights in France, and starred again as Ireland dispatched reigning champions South Africa 13-8 in Paris on Saturday night.
Mack Hansen claimed Ireland’s all-important try to stun the brutal Springboks, but Aki’s physicality dominated the midfield gainline battle.
And scrum coach John Fogarty was left in no doubt of the 33-year-old’s impact on the world’s No1 side.
“[Head coach] Andy Farrell talks about how you make people feel, in attack and defence,” said Fogarty.
“What you see from Bundee is real physicality, real energy on both sides of the ball.
“He does a huge amount of preparation so he is very clear in his mind what he needs to do in his game.
“That doesn’t go unnoticed by players, somebody spending so much time to make sure they are unbelievably well prepared.
“He gives so much energy, picking guys off the ground, he is vocal. He has got excellent footwork, real punch in his tackles and carries.
“He makes people feel good on the field. He brings real energy and he is having a hell of a tournament.
“For him to put in such a performance on his 50th cap, we are so proud of him.”
Andy Farrell’s side will now face Scotland in Paris on October 7, where a win would see them top Pool B.
Ireland will be desperate to move well past their quarter-final sticking point at this World Cup, and in that quest, it remains so far, so very good.
Ireland fended off South Africa’s onslaught in every facet in a consummate performance to underscore their status as World Rugby’s top-ranked team.
South Africa rolled out all their big guns in the pack, especially with their seven forwards on the bench.
But Ireland held firm, led by another towering performance from bullish prop Andrew Porter.
“Andrew was absolutely immense, across the pitch,” said Fogarty.
“To do what he did at scrum time and set-piece is one thing and something he can be very proud of.
“But to back it up around the field, his defence was excellent, his ability to get off the ground and give people energy.
“He took a few carries that he needed to make metres in and worked unbelievably hard. We are very lucky to have him.
“He is a resilient guy, he has real physicality and a huge engine and appetite for the game.”
