After climbing as high as third in the Premier League, the Baggies recently slipped off the pace with a four-game winless streak, starting with defeat at Swansea late last month.
However, Clarke's men have since recovered with successive triumphs over Norwich and QPR to move back up to sixth in the standings.
Olsson feels the manager's calm manner has been crucial to getting Albion back on track.
He told The Sun: "He is just calm and to me that's an indication of intelligence.
"When you are composed you think before you speak and are confident in the way you are playing.
"He is very calm, so can do anything under pressure. We want to be up there as long as possible."