The 25-year-old England international has netted just seven times for United this season and has been unable to recreate last yearÃ¢â‚¬â„¢s prolific 34-goal form.
Rooney tapped in UnitedÃ¢â‚¬â„¢s third in their 4-0 win over Wigan Athletic at the DW Stadium on Saturday but sparked controversy earlier in the game when he elbowed James McCarthy in an off-the-ball incident.
The United forward says a string of injuries has not helped him in his quest to rediscover his top form.
“I have to say it’s been a difficult season for me – probably the worst I’ve ever had,” he told the News of the World.
“That week when I asked for a transfer was something I wouldn’t want to go through ever again, but I feel I made the right decision to stay because this club is always going to be challenging for trophies.
“I picked up a few niggles as well and missed a few games, so I didn’t really feel like I was playing a part.Ã¢â‚¬Â
But Rooney believes the weeks he spent away from Old Trafford last autumn could work in his favour as the title race reaches its climax.
He added: “The good thing is that I feel fresh at a time when most players are picking up injuries or feeling jaded.
“I really want to kick on from here and have a big impact on the most important matches of the season.”
Rooney has shown signs of improvement in recent weeks and he admits his spectacular winner against derby rivals Manchester City earlier this month gave him a much-needed boost.
“The goal against City gave me a big lift because it was in such an important game,Ã¢â‚¬Â he continued. Ã¢â‚¬Å“I’ve seen it again quite a few times and I’ll never get sick of it.
“We’re happy with the position we have put ourselves in – and we know it could have been even better.
“This is usually the time of year when we really go for it. We want the title back. It was hard losing it to Chelsea as we did.”
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