The Hammers had taken the lead inside two minutes with a strike from Robbie Keane but Villa wrestled back control with Darren Bent's header shortly before the interval. West Ham goalkeeper Robert Green pulled off a string of saves to keep his side in the game but Villa snatched a deserved victory with a header from substitute Gabriel Agbonlahor in added time.
"I must give credit to their character because that is what we need when we are in a fight against relegation, you need character and you need composure," said Houllier.
"At times we demonstrated well that in difficulties the team was together and working well.
"When you are in danger you can't have egos in the team and you can't have grudges. You have got to be man enough to put away your own personality and work for each other.
"We were was disappointed at half-time. I said: 'We can win this game'.
"I said to the players before the game that this was a turning point. We missed a turning point at Bolton when we went 2-1 up and we lost the game. I said to them that we would not miss this turning point.
"We were stung and it took us 15-20 minutes to get the spirits right because of the goal we conceded.
"I know every point is valuable but I thought we went for the win right from the start and got the reward. It may have been late but we got it.
"We created chance after chance. We created enough to win the game and from a heart point of view it is not good to wait until added time to score."
Source: PA
Source: PA