Wallabies second rowers Will Skelton and Kane Douglas were sent to the sidelines during training on Wednesday by coach Michael Cheika after a heated and physical exchange as opponents in a driving maul after a lineout.

The unofficial yellow carding of the pair would be costly and earn Cheika's ire in the locker room afterwards were it a game, but the Wallabies coach was brimming with delight behind the duelling duo as they walked off.

Chin music: Will Skelton and Kane Douglas during the testy encounter at training. Credit:Brendan Esposito

The physicality of the Wallabies forwards at Kippax Oval at Moore Park in the morning session was just what Cheika was wanting of his two packs in the squad of 31 that leaves on their World Cup campaign on Saturday.