Watford boss Javi Gracia felt defeat at Chelsea was caused by a failure to take their chances before halftime.
A quick-fire double from Ruben Loftus-Cheek and David Luiz at the beginning of the second put Chelsea in control with Gonzalo Higuain adding a late third for the 3-0 win.
Gracia said: “I think the result was very, very tough for us. In my opinion we didn't deserve it. It's true we had some good moments in the first half, a good performance, creating good chances and dominating the game because in that moment we played in the opposition half, we recovered the ball after losing it with a very good attitude and we were very ambitious. But we didn't take the chances and we didn't confirm.
“We have to be more clinical in that situation, more aggressive in both areas because in the first half we had the chances and in the second half we conceded two goals from set pieces. It's difficult to say I'm happy with the performance because losing 3-0, I am not happy."