The Waratahs have won back-to-back matches for the first time in 19 months and consigned Melbourne to more Super Rugby Pacific misery with a 24-19 victory at the SCG.

After beating the Western Force last round the Waratahs backed it up with a hard-fought victory on Saturday night over the winless Rebels, who were at least in the contest after their best performance of the season.

"Wins are always pleasing but I wouldn't say that's a performance to be proud of - there's a lot to work on there," Waratahs skipper Jed Holloway told Stan Sport.

"We were messy getting out of our own end and our lineout had some issues throughout the whole game."

The home side led 14-6 at halftime with tries by No.8 Will Harris and centre Lalakai Foketi.

Harris risked the wrath of coach Darren Coleman by ignoring two unmarked teammates outside him and electing to drag two Rebels across the line.

Foketi earlier did his chances of Wallabies squad selection on Sunday no harm when he split the defence with a power run to the line.

But as has been the Rebels' story of the season, they struggled to complete most attacking raids despite some nifty work by centre Ray Nu'u and young winger Glen Vaihu with fullback Reece Hodge also toiling hard.

They were kept in the match by four penalty goals by five-eighth Matt Toomua, who temporarily left the field after a first-half head knock.

The knock-out blow looked to have come in the 54th minute when Rebels reserve hooker Efi Ma'afu was given a yellow card for a lifting tackle, with Waratahs winger Alex Newsome crossing in his absence.

But Melbourne prop Cabous Eloff burrowed over in the 67th minute to put his side back in the game, trailing by five points.

However in the scramble they weren't able to conjure a second try to close the gap, with back-up playmaker Carter Gordon in tears post-match after booting a ball dead which wrecked a late chance.

"Definitely closer than the first couple of weeks, we're managing to attack more cohesively," a disappointed Rebels captain Michael Wells said.

"I thought we controlled the game better and game management was better from a leadership point of view.

"We didn't execute 100 per cent but it was better."