The Hammers are currently on a run of three consecutive wins, without conceding a goal, and Diame feels the side can continue their rise up the table with positive performances.
The 26-year-old had a significant influence in Tuesday's 2-0 victory over Norwich City, after coming on just after the hour as substitute, setting up James Collins' goal and then converting one for himself in the final minute of the game.
Speaking to the club's official website, the Senegalese international said: "It's great for our confidence. If you want to win games you have to make sure you are strong in defence and not concede goals.
"If you don't concede you can't lose, so the team is doing well. We need to keep going and stay focused on what we're doing to make sure this break before our next game doesn't stop the momentum."
Diame also praised goalkeeper Adrian, who has kept four clean sheets in a row, saying: "I think he was unbelievable on Tuesday, Adrian is a very good goalkeeper and good with his feet as well.
"He made a lot of saves on Tuesday, and he's done that since he started to play for West Ham. I hope he continues like that."