Ba scored the only goal of the game.
"We had a very good game, all together, the whole team," he told chelseafc.com.
"The combinations that we made were very good and yes, we could probably have had more than one goal but on the day it was enough and at this time of year we take it.
"Chelsea played the sort of football I came here for. We created a lot of chances and congratulations to the defensive part of the team because they [West Brom] didn't create a lot of chances so it was a very good team performance.
"It was important to win because with Spurs and Arsenal facing each other, we knew at least one of them was going to lose points."