The Baggies boss was speaking after Saturday's 2-0 victory over Crystal Palace at The Hawthorns, where the England international shone again with an impressive goal against the Eagles.
According to Clarke, Berahino is ready to commit his future to the club, after bursting onto the scene this season, and is not paying any attention to speculation linking him with other clubs.
That said, he hopes that West Brom will reach an agreement with the 20-year-old sooner rather than later, given that Arsene Wenger and Jose Mourinho have both been credited with an interest in the player.
"We are in negotiation with his representatives and if I was the club I'd get it done as soon as possible," said Clarke. "He's hungry and he wants to play.
"This contract is important but it's not the most important one he'll ever sign, that's further down the line. I think he is happy to work with me."
Arsenal and Chelsea are both understood to have sent scouts to watch Berahino this season, following his encouraging early displays in 2013/14, but their respective hopes of luring the youngster to the Emirates Stadium or Stamford Bridge will be dealt a blow if he pens a new long-term contract.