However, Bakary Sako struck with 15 minutes remaining to provide Wolves with a two-goal cushion and Cotterill is convinced that the scoreline does not accurately reflect his team's effort.
He told the club's official website: "I think 3-1 is harsh on us to be honest. We were positive at half-time but I don't think we'll get get credit for our performance today.
"We won't be negative. We'll get the lucky breaks on another day. We have to remain upbeat."
City, who remain second from bottom in the League One standings, travel to Griffin Park for a clash with leaders Brentford on Tuesday.