Carlos Corberán believes Albion's lack of clinical edge proved the difference in their defeat to Sunderland on Sunday afternoon.
The Baggies hosted the Black Cats knowing that a win could have lifted them into the top six of the Sky Bet Championship.
Despite taking the lead in first-half stoppage time through John Swift's penalty, two Dennis Cirkin goals in the second half earned the visitors the spoils - a result which the boss believes came down to Albion's inability to take their chances in the fixture.
He said: "Unfortunately we couldn’t get the result we wanted to get."
"The fans created an amazing atmosphere and the players played with the right intensity to compete in the game.
"We tried to be very aggressive because we knew that when they have the ball in the attacking half they are a very ambitious team. We wanted to avoid these type of moments and I think in the first half the team didn’t compete at the level that the game was demanding.
"In the second half we increased the aggression, especially in the attacking half and we created more chances than them.
"For me, it’s a game that’s been won by the team that were more clinical in the opportunities they had to unbalance the game.
"We knew that the game would be a very good game to watch from the fans’ perspective because it involved teams who like to play well."
The result leaves Albion still chasing the Play-Off places, but the boss insists that his side need to react quickly with their fate remaining in their own hands.
"Football is never going to be easy, and in these type of situations they key is to have the right mentality to overcome difficulty." He said.
"Today has been one more moment like this, and we will react again. To win these next games is very important to put the team in the highest position.
"After one defeat, you can’t overthink it too much. But at the same time, there’s just two days between the games – we know how important the next game is going to be.
"The most important game is always the next one. Forget the previous one, prepare for the next one in the best way we can."