But with 22 minutes remaining, Manu brought the defending champions back into the game with an incredible solo try.
On an attacking raid, a ball went to ground into back play, but Manu burst off two tackles and slid into the in-goal.
The question was asked however if it was another double movement.
Greg Alexander was confident it was a try but Steve Roach wasn't so sure.
"I don't know, has he advanced the ball?" Roach asked.
But Alexander was confident. "That's a try every day of the week," he said.
"We try to look at things and pick them apart when we should just react to how it happens on the field, how it's seen live."
It set up a grandstand finish with a 37-year first still on the line.
But the Raiders then responded as George Williams put in an awkward grubber that wrong footed James Tedesco with Wighton grounding it in goal to re-establish a 10-point lead.
"What a cruel bounce at the back there from James Tedesco, he didn't deserve that bounce, but he chased so hard Jack Wighton," Roach said.
It was particularly brutal for Tedesco who had run 264m with eight tackle breaks in a masterclass performance at the back.
It didn't take long though for the Roosters to hit back with a Sonny Bill Williams' offload going to Sitili Tupouniua, who tossed it on short to Tedesco to redeem himself.
But with just a minute remaining, Tedesco was again involved, reaching for a pass in front of him to knock on.
The Raiders held on for one more set, leaving the Roosters one last kick but it wasn't enough as Canberra moved on to play the Melbourne Storm for a place in the NRL Grand Final.
