Kouyate scored the crucial first with a superb header early in the game and played his part in the Hammers recording their third straight victory.
He told whufc.com: “We are very happy with the result because we beat a big team like Chelsea. The most important thing for us was to get the victory and we managed to do that.
“I saw my goal after the game and it was an unbelievable goal. I spoke with Dimi and said it had nothing to do with him this time! But I am very happy to have scored the goal.
“It was great to see Fernandes score and he is a very good player. He works so hard and I was very happy for him. We are now all focused on the next game.
“We have been working hard the last few weeks and are now getting some good results. We will stay humble because we want to continue winning.
“Last season we wanted to reach Wembley so why can’t we do it this season.
“The new system is very good and I am enjoying the position. Every player has to work hard in the system and we have been doing that. The spirit has always been there.”