The in-form 20-year-old started Saturday's game on the bench, but he was called into action after just 31 minutes of the Premier League clash at The Hawthorns as Billy Jones was forced off the field clutching his leg.
And it was not long before the youngster had made a telling impact, with his 44th-minute effort giving the home side a lead that they eventually doubled through Gareth McAuley on the way to a 2-0 victory.
It was yet another superb performance from Berahino, whose all-round displays have been rewarded with three goals for the club in all competitions this term.
And Clarke admitted afterwards that West Brom will do everything in their power to agree a contract extension with the Burundi-born forward as soon as possible.
"He's had a good season and long may it continue," Clarke said. "We're in negotiations with Saido's representatives and if I was the club, I would get it done as soon as possible.
"I don't think (any increase of salary or profile) will affect Saido, he's hungry, he wants to play and he's a young boy who wants to make his name in the game.
"This contract is important to him but it is not the most important contract he will ever sign, that's further down the line.
"All I would say is he's a young boy that eight weeks ago nobody was talking about, so you have to keep the level of expectation down and in this country we are too quick to push people forward as the next big thing."
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