The manager told BBC Sport: "Diego Costa is one of the best strikers we have at this moment in football. The team is an attacking team that creates a lot, creates spaces for a striker. The second goal is a brilliant collective action and Cesc Fabregas had a fantastic assist.
"We were too comfortable in the first half, not creating super dangerous situations. In the second half we started pressing them very well, did not give them time to play, started creating and playing more attacking football. It could have been five or six."
The result leaves Chelsea at the top of the Premier League table with maximum points.