The French striker missed two good chances on Sunday as the Baggies were held to a 1-1 draw at home to Arsenal in the Premier League.
Anelka has now failed to find the net in his first five games for West Brom following a summer move from Shanghai Shenhua.
"Nicolas is an experienced striker and he knows he was in the right position. The first chance actually arrived a little bit behind him, which meant it was difficult to finish," Clarke told the Express and Star.
"For the second one he did almost everything right. He opened the goal up and just put it the wrong side of the post - we're talking inches.
"On another day he could have scored both. Strikers need goals and Nico is experienced enough to know if he keeps getting in those positions he'll score goals."
West Brom return to Premier League action on October 19 when they face Stoke City at the Britannia Stadium.