On 24 February 2010, he scored a goal against Internazionale in the Champions League round of 16 first leg. His shot from outside the box was tame but an error from Inter goalkeeper Júlio César allowed the ball to find the back of the net in a 2–1 loss. In Chelsea's 7–0 win over Stoke City on 25 April, Kalou netted a hat-trick, though his second goal of the day had been the source of controversy, as it was very close to being a two-footed tackle. Kalou scored Chelsea's third of eight goals on the last day of the season against Wigan, as the Blues were crowned champions.