Yacob joined the Baggies last summer on a free transfer from Racing and has made a good impression in his first season in the Premier League.
"When you get a player like Yacob and he turns out to be as good a player as he is for the team, that's great," Clarke told the club's official website.
"Normally a player of the type of Claudio is a players' player, a managers' player or a coaches' player and doesn't really stand out – he just does his job for the team. I think he's been tremendous and a big, big bonus for us."
West Brom face off against Swansea City in the Premier League on Saturday.