Big win for the Rebels could come at a big cost

Melbourne's big Super Rugby win over the Sunwolves has come at a cost with Test halfback Will Genia knocked out.

The Rebels kept their quest for a maiden finals appearance on track with a 52-7 bonus-point win over the Sunwolves on Saturday in hot conditions in Tokyo.

Recording their highest score in Super Rugby, they remain a point behind the conference-leading Brumbies, who had a win on Friday night over the Bulls.

Wallabies winger Marika Koroibete continued his run of impressive form, picking up two tries and setting up a third, among the team's haul of eight.

Fellow flyer Jack Maddocks scored a brace as well, while Rebels playmaker Quade Cooper had a hand in many of the five-pointers.

World Cup hopeful Jordan Uelese made his first appearance of the season after a knee reconstruction, looking fit off the bench, and collected a try from a maul after the final siren.

Skipper Dane Haylett-Petty was delighted by the performance after a d isappointing loss to the Bulls last round.

"We are obviously very happy with that," the fullback said.

"It was definitely a must-win game for us but I think they all are down to the pointy end of the competition."

But Genia might miss Friday night's crucial showdown with the NSW Waratahs at AAMI Park.

In the first minute of the second half, Sunwolves wrecking ball Amanaki Mafi ran over the top of Genia, with the halfback's head collected by the boot of centre Phil Burleigh as he ran through.

Genia managed to walk from the field, but looked dazed. The only upside of the injury was that reserve halfback Michael Ruru impressed, scoring a try, after limited game time this season.

Apart from the Genia blow, the Rebels looked sharp against the struggling Sunwolves.

They led 19-0 at halftime thanks to a try by flanker Angus Cottrell and Koroibete's double.

That was pushed out to 31-0 before the home side finally made it onto th e scoreboard in the 62nd minute when fullback Jason Emery charged down a Reece Hodge clearing kick and won the race to the ball to touch down.

Melbourne's set piece also deserved praise. The Rebels' pack dominated the lineout and scrum to give plenty of go-forward for their backs.

Haylett-Petty said the Rebels were particularly pleased with their defence, limiting the Sunwolves to just one try.

"We know we are a good attacking team but I'm really proud of the defence today - we knew we needed to improve on that," he said.

"We wanted to be physical, especially in our forwards, and they really stood up today and set a good platform."

- AAP