The Spain international scored an 89th-minute winner in a 2-1 triumph over the Hammers in their Premier League opener at Stamford Bridge tonight.
It could have been a different result had Costa been sent off earlier in the match when he lunged in on Adrian as the keeper tried to move the ball with his feet.
The controversial striker was already on a yellow card, but the match official decided that his foul was not deliberate.
When asked about the incident, Conte told Sky Sports News. "I didn't see the situation but on the bench I saw that Diego put pressure on the keeper and then tried to stop, but in my opinion the referee took the right decision."