Michael Schumacher admitted age was finally catching up with Formula One's most successful driver after announcing his retirement.

The 37-year-old won yesterday's Italian Grand Prix before revealing he will quit racing at the end of the season.

Schumacher delivered a consummate display to beat Kimi Raikkonen, his replacement at Ferrari, to the chequered flag but confessed he feared losing that extraordinary turn of speed.

"You can see what I am able to do now but you need all the energy and motivation and getting older doesn't make it easier to keep that," he said.

"I just couldn't see it happening. I don't need to worry about anybody with the skill I have but it is nicer to go at this point than at the other end."

Schumacher's time at Ferrari has seen him rewrite the record books, five consecutive titles installing him as a true sporting legend.

Monza proved to be the perfect location to make his momentous announcement after a decade with the Italian team.

"Monza is just unbelievable," he said. "It has always been very special, in particular after the race when all the fans are around to celebrate so close with us.

"Due to the circumstances, it was an unbelievable feeling I had out there.

"It has been a very special day and we finished it in style, looking at the championship as well, but much more at what is going to happen in the future."

Schumacher's place will be taken by Raikkonen next season, when the 26-year-old joins from McLaren.

The Finn accepts he has a huge weight of expectation on his shoulders when he replaces the most successful driver the sport has seen but is confident in his own ability.

He said: "Of course it is a nice place to go. The team and the fans will expect a lot but in the end I also expect a lot from myself - I want to win.

"It will not be easy but I will go there and do my best - hopefully it is enough."

Raikkonen refused to reveal when he decided to join Ferrari, despite long-standing rumours of the switch, but claimed he needed a new challenge.

"There are many reasons but in the end, after five years at McLaren, I wanted something else," he added.

"I think there were only two choices, to stay at McLaren or choose Ferrari. I wanted to go there one day and this was the best moment.

"It is a great day to join. Sometimes you want something different in life."