Kepa is on-loan from Spanish side Sevilla, and scored within 60 seconds of coming on in his debut against Liverpool on Tuesday.
He said: “I’ve got a taste for playing in the Premier League after the Liverpool game.
“I am happy about scoring, but it really doesn’t help the team because we lost a game that was very important for us.
“I honestly would have preferred not to score and for West Ham to have won the match. I believe that this team has a chance of staying up. The key will be the mentality of the players.
“We need to go out on to the pitch forgetting that we’re in the relegation zone and play more relaxed and without any nerves.
“Personally, I feel good so it’s all up to the coach now.
“I’m getting to know my team-mates well and I believe that the English style of play will fit perfectly with the way I play.”