The striker headed home after the break after Phil Jones had opened the scoring in the first half. Danny Welbeck came off the bench to add a third and seal the victory, and Rooney believes the win could be vital ahead of some tough upcoming fixtures.
"It is a confidence-booster," he told BT Sport. "We've got Liverpool and Olympiacos next, where we're two goals behind [after the first leg], followed by West Ham and Manchester City. They're all big games. It's a good challenge and it's down to us as players to take that challenge on and show everyone we're a good team that means business.
"We were hurt after the Olympiacos game, and we needed to go out and show everyone that we are a good team. We'll fight for the shirt, and we'll fight for a place in the team, and I think that showed today. We played with a great energy, we were exciting and we always looked a threat, so I think we deserved the three-goal win. And it could have been more."
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