The Frenchman scored one of the goals as the Hammers shrugged off Michael Obafemi's equaliser to triumph 3-1 and lift themselves out of the bottom three.
Haller said, "In every game we need to [go for the] win because in our position we have no choice - we just need to get points.
"It doesn't matter how we get the points, but we need to win, so today is a massive result.
"You can see that everyone worked really hard for it and it's satisfying. We need to be focused on the next game now.
"I really wanted to score [and I took that chance]. Me and the team are really happy for Jarrod (Bowen) to score too. Hopefully he will score even more goals."
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