The centre half was a key figure during the Blues' 3-2 win over the Albion on Sunday at Stamford Bridge.
Colwill, who scored in the game, spent time on loan at Brighton last season and did not celebrate his strike.
“I guess it's somewhat slightly bittersweet for me in the sense that it's come against Brighton, a club that means so much to me, but I'm really pleased to help the team get the three points.
“The goal meant a lot to me but I also wanted to show respect to Brighton. We needed that victory and that's what matters the most, so I'm really pleased.
“I've got so much respect for Brighton as a club. I wouldn't be where I am today if it wasn't for them, so I've got a lot of admiration for them and for the manager there.
“There's no hiding from that but listen, I play for Chelsea and this club means so much to me as well. I had a job to do and I'm just glad we got the win as a team."