"For the first few games it takes time to reach your best," he said. "But I haven't really had a full pre-season - by October you should be hitting your top form, so that's probably one reason why I play better then."
Rooney, who has matched his regular strike-rate for United with three critical goals in England's World Cup qualifiers against Kazakhstan and Belarus, found it difficult to disguise his delight at the resurgence.
"It's brilliant, you practise to make things happen in games," he said, while offering a reflection upon a momentous year in his development.
"Winning the Premier League and Champions League in the same season was a great achievement by the team. It hasn't happened in football many times.
"And then on a personal level, getting married was something I was really excited about and proud of. It has been a great year for me."
Although a Premier League winner's medal was the one he most aspired to as a child of Croxteth, he acknowledged that the sensation of his first Champions League glory was one he would struggle to eclipse.
"One of the reasons I left Everton to join United was to play in the Champions League and try to win it," he told Inside United magazine.
"To win that was unbelievable; I think because we had won the league the year before as well, the Champions League was sweeter. To beat Chelsea in the final and win it on penalties was obviously a great feeling."