New halves pairing for the Rebels in do-or-die match with Crusaders

Melbourne will field a new halves combination for their crunch Super Rugby match with the Crusaders, with Australian Test star Will Genia rested and Quade Cooper named on the bench.

The Rebels are looking to knock off the overall competition leaders and defending champions in Christchurch on Saturday to cement a finals berth.

New Wallabies recruit Matt Toomua will start at five-eighth with Michael Ruru at halfback, with Genia's rest enforced by Rugby Australia.

Rebels coach Dave Wessels said the break had been pencilled in months ago and he was comfortable with it.

"From a performance perspective when we get to the play-offs we want to thrive - we don't want to limp in with tired bodies and both Will and Quade have played a lot of minutes for us," Wessels said.

"It's a sensible time not only from a Wallabies perspective but from a Rebels perspective to give those guys some time out.

"It hasn't been a hard decision."

In-form winger Marika Koroibete must also start on the bench as part of the Test player rest policy, while hooker Jordan Uelese gets his first Super start of the season.

Wessels stressed the changes weren't about targeting their final round home game against the Chiefs, which appears more winnable as they try to finish in the top eight.

"We don't have that luxury to be taking things easy here - we have to fight for every opportunity and this is an opportunity," he said.

"There's a couple of guys in this group who've had some success in Christchurch and the group is feeling good.

"The Crusaders are a hell of a good side but they have been frustrated by their form - I think they've won two of their last five - but there's no doubt we're going to have to play really well."

Wessels said the team was bitterly disappointed by their five-point loss to the NSW Waratahs last round but he felt they'd rallied well at training.

"We were down because we didn't play well and that's been the frustrating thing. When we're on we feel like we can beat anybody."

Rebels: Dane Haylett-Petty (c), Jack Maddocks, Reece Hodge, Billy Meakes, Tom English, Matt Toomua, Michael Ruru, Isi Naisarani, Richard Hardwick, Angus Cottrell, Adam Coleman, Matt Philip, Sam Talakai, Jordan Uelese, Tetera Faulkner. Reserves: Anaru Rangi, Matt Gibbon, Jermaine Ainsley, Luke Jones, Ross Haylett-Petty, Harrison Goddard, Quade Cooper, Marika Koroibete, Sam Jeffries.