Scotland will require one of their "best ever performances" if they are to beat Ireland and reach the quarter-finals of the Rugby World Cup, says head coach Gregor Townsend.

With South Africa likely to take five points from their match with Tonga on Sunday, Scotland would need to beat Andy Farrell's side while also denying them a bonus point in order to reach the knockout stages.

"We knew we had to win this game to still be in the World Cup, and a bonus point means we know what we need to do next week," Townsend said on ITV.

"We've got to produce probably our best performance of the year, one of our best ever performances. That's the whole goal of why we work in training, what we've learned this year. We have to bring that out for 80 minutes."

Scotland were rampant on the night, admittedly against a Romania side who offered very little, but Townsend was delighted with the way his players approached the task in hand.

"Their attitude all week has been excellent and they did a professional job," he added. "It was hard work, physical, the ground was wet, but some of the individual tries, and more importantly the teamwork, was excellent.

"There was a togetherness in the squad. The players realised they have to produce quick ball, Romania would come out and take the game to us. They were very physical at times.

"We just stuck to our task, whether there were players off with yellow cards, whether we'd just scored, or whether we'd gone through a fallow period. That focus was really good to see."

'One of the best in the world' - Graham steals the show

With four tries, 211 metres made and 14 defenders beaten, Darcy Graham took all the plaudits for his try-scoring blitz, as he climbed to joint second on Scotland's all-time try-scoring list and became just the second man, after Gavin Hastings, to score four tries in a single World Cup game.

Scotland great Scott Hastings called him "scintillating", and added that he "has a relish for that tryline", while Graham's former team-mate Greig Laidlaw described him as "one of the best in the world for stepping in tight spaces".

Graham himself was humble after the game, choosing to praise the team's collective performance rather than focusing on his individual achievements.

"I got through lots of work today - we spoke about being disciplined, keeping hold of the ball, sticking to our game and things will fall into place," he said. "The boys did that well and I'm proud of them tonight.

"We just wanted to get this game out the way, get the five points and fire into Ireland. We're going to go to Paris all guns blazing and put in our best performance. Time to rest up and kick on."