The Belgium international, on loan from Chelsea, took his English Premier League tally for the season to 12 goals with a brace at The Hawthorns on Saturday.

Lukaku opened the scoring from the penalty spot before charging down a clearance from Sunderland goalkeeper Simon Mignolet for his second.

Clarke praised the striker for his efforts and said his loan move had been good for all three parties.

"Lukaku is in a really rich vein of form. You could see that with his second goal, when you're playing that well you get a little bit of luck," he said.

"Physically, he's a great specimen, but he has quick feet for a big man. It's been good for us, good for Rom, and probably good for Chelsea as well."

Lukaku was replaced by Peter Odemwingie in the 87th minute, with the Nigeria international greeted by boos and a smattering of applause.

The 31-year-old tried to force a move to Queens Park Rangers in January, driving to Loftus Road despite never receiving permission to speak to the club.

Clarke urged fans to move on from the Odemwingie incident.

"I never noticed it (the boos) as I was too nervous about throwing away a two-goal lead," he said.

"But with his first touch he had a shot that went just wide. He got good applause for that, and I think the supporters would have been happy to see that go in.

"The Odemwingie thing meant I could never affect what the supporters are going to do. He's part of my squad and we're going to use him.

"He was always going to come back in at some stage. For me it's finished, the incident happened but that seems like a long time ago now.

"We have to move on and so should everyone else."

Sunderland manager Martin O'Neill felt his side deserved to at least draw the clash, saying they should have been awarded a penalty for a handball by Gareth McAuley.
"I felt we should have got something out of the game. That's the last three matches we've played where we shouldn't have been beaten," O'Neill said.

"The big decision was the penalty kick which was given against us.

"But then there was a similar situation at the other end where it wasn't given. I've seen both of them back. Both are penalties."