Rugby World Cup 2015: Too many quality options for Wallabies?

Dominant Australian loose forward duo Michael Hooper and David Pocock. Photo / Getty

It's the sort of headache not even the strongest of painkillers will relieve.

With vice-captain Michael Hooper back from suspension, and star No.8 David Pocock seemingly on track to overcome a calf complaint, Wallabies coach Michael Cheika has to work out who of five outstanding back-rowers to omit for Monday Rugby World Cup quarter-final with Scotland at Twickenham.

But it's one he will be welcoming, according to Hooper.

"It's not a headache - it's great to have that problem," Hooper said.

"It's tough for the coaches and I am happy I am not in that position, so you just want to get picked and have a jersey."

Hooper's return will allow Cheika to return to his first-choice back-row of Scott Fardy, Hooper and David Pocock, who have become a formidable force at this World Cup for their complimentary styles of attack, defence and ball-hunting.

And while it would seem the natural choice, it overlooks the sterling performances of Sean McMahon and Ben McCalman - both of whom put in terrific shifts in the 15-6 win over Wales.

McMahon, starting in Hooper's No.7 jersey, carried the ball with vigour and rattled the ribcage of Welsh No.10 Dan Biggar with a brutal front-on tackle - while McCalman held the powerful George North up over the tryline, described by Will Genia as the match-winning play.

While both would comfortably slot into the starting line-up, the stark reality is that one of them is almost certain to miss out on a spot in the match-day 23 should Pocock (calf) prove his fitness.

"Seanny has done nothing but impress me since the Spring Tour last year," Hooper said.

"Each opportunity at training and on field, he takes it.

"(He had) a really good 45-50 minutes on the weekend and then "Dog" (McCalman) on the back of that was outstanding.

"When you get an opportunity, you want guys to take it and Sean has done that and been great for the group as a whole, on and off the field."

Meanwhile, Hooper joked he burnt enough calories through nervous energy during the historic win over Wales to equal any fitness session he's had this tour.

Hooper was sidelined through suspension from victory at Twickenham, which delivered the Wallabies top spot in Pool A and set up this Monday's quarter-final with Scotland.

And he could do nothing but nervously shift in his seat and tap his feet as his depleted teammates defended their line for seven minutes with two men in the sin bin.

"It was really tough," he said.

"Like I said going into the week, you always want to put your hands up for selection and, when you have no say in the matter, it's really difficult.

"Going into the game, I knew it was going to be tough but, in that period when we were around our line, we were all in the stands curled up in a ball, so much tension and excitement and relief and so proud of the boys to get out of that situation.

"It was a new perspective for me but really exciting for the team."

-AAP