Seven-time Formula One world champion Michael Schumacher says he will retire at the end of the season, bringing a definitive close to a stellar career after a less-than-successful comeback.
The 43-year-old, who previously quit the sport in 2006 before returning two years ago, said he had decided to call time on racing after it was announced last week that McLaren driver Lewis Hamilton would move to his Mercedes team next year.
British star Hamilton, 27, won the drivers' world championship in 2008.
Schumacher's decision on Thursday effectively ends a hugely-successful 21-year career in the sport and more than 300 races, during which time he has become one of the world's most recognisable and successful sportsmen.
"I have decided to retire at the end of the season," the German driver told an emotional press conference in Suzuka, where the Japanese Grand Prix will be held on Sunday.
"I still feel I am capable of competing against the best but the time sometimes comes to say goodbye and this time it might be forever."
Since the announcement about Hamilton's move, speculation had swirled that Schumacher could continue his career with another team, with Swiss outfit Sauber expressing their interest.
But Schumacher said that although he still felt he could compete - and vowed to concentrate on the remaining races this season - he no longer felt the same drive to race on.
"During the past month I was not sure if I still had the motivation and energy which is necessary to go on," he told reporters.
"It is not my style to go on if I'm not 100 per cent with it but with today's decision I feel relieved.
"I have been thinking for quite a while (about retirement)," he added, saying that as he got older, it was hard to stay motivated.
"It's natural you think about this more than when you are young," he said.
"I have had my doubts for quite a while whether I had energy to (carry on). I said in 2006 my battery was empty and now I am in the red zone. I don't know if there is time to recharge them but I am looking forward to my freedom.
"I have no hard feelings. In a different way we achieved a great deal... Now I will do exactly as I did the first time - to finish and focus 100 per cent on what I do next."
Schumacher won 91 races between 1991 and 2006 - two world titles with Benetton in 1994 and 1995 and five consecutive with Ferrari from 2000 to 2004.
He retired from Formula One for the first time in 2006 before returning in 2010 on a three-year contract with Mercedes.
His comeback, however, failed to match his spectacular early career and he claimed just a single podium finish in 52 races.
"We did not achieve our targets but I can be happy about overall achievements in my career," said Schumacher who is currently 12th in the overall standings, 151 points behind Spain's Fernando Alonso.
Schumacher's retirement will come after the Brazilian Grand Prix at Interlagos on November 25.
Mercedes team principal Ross Brawn and motorsport boss Norbert Haug were at Schumacher's side when he made the announcement.
"I thank Michael," said Haug.
"We have known each other a long time. We started together in Group C racing and he went on to be the most successful driver in Formula One, winning more races and titles than any other driver.
"We were competitors against him (when Schumacher was at Ferrari) and we had always dreamed of working together and it came after Brawn Mercedes won the World Championship in 2009.
"We did not achieve what we wanted to but Michael has laid some strong foundations and I want to thank him from the bottom of my heart."