The league leaders missed the chance to go four points clear of Arsenal and five ahead of Manchester City when they drew 1-1 at The Hawthorns.
Victor Anichebe's late goal dened Jose Mourinho's side, but January signing Matic is eager to put that disappointment behind him.
"I said after the Man City game (which Chelsea won 1-0) that we'll fight until the end of the season," Matic told the club's official website.
"We need to take it game by game and play as well as we can in order to win matches. At the end of the season we'll see if we can be champions.
"We always believe, we just try to improve and give our best. We have a young team, we are not favourites but if we have a chance to be champions we want to take it.
"We are not happy because we drew 1-1, we came here to win but that's football, that's life. Now we have to concentrate on the next training session and next game."
Branislav Ivanovic's first-half goal looked to have put Chelsea on course for victory, but Matic admitted the London club lost their way after the break.
"In the first half and for 10-15 minutes in the second half we played very well but I don't know what happened in the last 30 minutes," Matic added.
"We lost our concentration and West Brom were playing long balls, we didn't know how to deal with it and they caused us a lot of problems.
"They scored a goal in the last few minutes but football is like that sometimes, you can win in the last minutes but you can also lose points. We had some chances to make it 2-0 which we didn't take and it's difficult to speak about it.
"It's not easy when you concede a goal with four minutes left, after that it was hard for us to do anything."
