The striker celebrated signing a new long-term contract by scoring in the victory.
"I've been trying to do well for the team and trying to help us win," he told Sky Sports 1. "Whether I'm signing a new deal or not I always give 110 per cent on the pitch and that's what I've done today.
"It's been more or less agreed for a month now and it was just the fine details that needed sorting. I wanted to get it done as quickly as possible and thankfully it's behind me and I can concentrate on my football.
"Obviously I've been letting my football do the talking but I'm happy and settled."
Turning his attention to the victory at Selhurst Park, which lifted United into sixth place and to within five points of Tottenham, Rooney added: "Today was a big result for us.
"It was a good victory. I thought we played well and it was a good win.
"We moved the ball well, maybe could have created more chances but overall we were in control of the game and once we got one goal we knew we'd get another and see the game out.
"It's tough getting that first goal but thankfully Robin put the penalty away and I think it was a great three points."
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