It was a rare start for Lukaku who has been kept out of the side for most of the season by leading scorer Shane Long.
But he justified his selection as his goal ended Norwich's 10-game unbeaten run in the Barclays Premier League and moved Albion back into the top six.
Clarke said: "Romelu has done well, he is a big talent, he has got a big future ahead of him in the game.
"The fact he couldn't get in the team for most of the season is down to the form of Shane Long who shouldn't be forgotten today.
"Shane made a difference when he came onto the pitch, he tied up the other centre-back, has given a bit more space to Romelu, and maybe that's why he has got the space for the winning goal.
"It's a team effort and we don't like to single out individuals."
Lukaku had chosen the rap song 'The Question (What Am I Doing Here)' as his musical choice which was broadcast before the game.
Clarke quipped: "At the moment he is doing okay so that's the answer to that one!"