Valentino Rossi's performance in overcoming his worst start to a grand prix season to lead the MotoGP series as it enters its final round in Valencia tomorrow has again sparked the debate: is he the greatest motorcycle racer ever?
A series of crashes and mechanical problems with his Yamaha had relegated Rossi to fourth place in the championship table after the US Grand Prix in July, 51 points behind the leader, Nicky Hayden, with only six races remaining. Now he leads the American - the only rider who can stop Rossi from winning his eighth title - by eight points.
It has been an incredible turnaround, marked by the 27-year-old, London-based Italian's refusal to give in. Admittedly, he was helped by the farce of the previous race in Portugal when Hayden was sent crashing out by his Honda team-mate Dani Pedrosa. But that is racing, as they say.
So is Rossi the ultimate? We asked the experts to examine "The Doctor".
Four times World
Superbike champion 1994-95, 1998-99
It's impossible to compare riders from different eras. To make a real comparison, you'd have to put, say, Kenny Roberts, Wayne Rainey, Carl Fogarty and Valentino Rossi in the same race when they were all aged 28.
All you can say is that Rossi is the best of his time. But I wonder if the opposition has been good enough. I've always said that you'll never get anyone to beat Rossi while you keep passing these older guys like Max Biaggi and Carlos Checa around the teams. You have to get young guys in, and that's what they're doing now with Casey Stoner, Dani Pedrosa and Chris Vermeulen. They could beat Rossi next year.
2003 World Superbike champion. Could be
competing against Rossi
in 2007 MotoGP series
I think Rossi is absolutely incredible - definitely the greatest of all time. He's one of the few riders I've seen who can constantly ride on the limit but rarely crash. He would have sewn up this year's championship a month ago if he hadn't had problems.I also can't see anyone beating him in the future. He could go on to win 10 world championships.
BBC TV commentator and former grand prix, superbike and TT racer
I think that Rossi became the greatest after he moved from Honda to Yamaha in 2004 and won the MotoGP championship when many people said it would be impossible. He's such a thinking rider, but riders like that are often not that fast, because they're wondering, "Why the heck am I doing this?" There's a fine line between intelligence and stupidity to be achieved, and Rossi's got that together.
MotoGP Official Statistician
Personally, I think that Mike Hailwood was the greatest. Things were certainly different in his time. He sometimes rode in three grand prix races in one day, for example. In the 1966 Czech grand prix, for example, he beat Phil Read in the 250cc race, Giacomo Agostini in the 350cc race, and Agostini again in the 500cc race. And races were longer in those days. That 250cc race was 50 minutes, the 350cc race 59 minutes and the 500cc event 76 minutes. That's more than three hours racing in a day on one of the dangerous old-style circuits.
Maybe the fastest rider I've ever seen on a bike was the American Freddie Spencer. And the greatest single feat that I've seen was when Spencer won the 250cc and 500cc world championships in the same season in 1985.
But Spencer didn't do it for long enough. Rossi's strength is being able to do it for year after year.
Race Director, MotoGP championship
The title "greatest ever" is probably between Mike "the Bike" Hailwood and Rossi.
They both earned the utmost respect from their fellow racers as a result of their genius on a motorcycle and their humility in victory.
Mike's era was one of black racing suits, little or no commercial exploitation, and amateur organisation. But Rossi's genius has flourished in a period of colossal audience growth, and the demands on his time from commercial partners, media and the fans bear no comparison with previous eras.
What we can say is that Rossi is the first and only MotoGP champion so far to achieve global superstar status. This results in equal parts from his infectious charisma and his other possession - the best ever internal gyroscope on a motorcycle.
Grand prix, superbike and TT rider of the 1980s
The most naturally talented rider that I've seen has to be Rossi. One of his great strengths is that he manages to totally enjoy what he does - he doesn't allow the job to become a chore, even though much of it is. And a happy rider is a fast rider.
But Mick Doohan would come a very close second. Doohan lifted the bar by becoming a super-athlete. You would see Wayne Gardner and Kevin Schwantz having a beer on Sunday night after a race, but not Doohan. He knew that by not doing it he would have a psychological advantage.
Another thing that he achieved was to come back after a life-threatening accident in 1992 and win five world championships. How mentally strong do you have to be to do that?
Magnificent seven The riders Rossi has to overtake to be No 1
* GIACOMO AGOSTINI (right) (It) 15 world titles in 1960s and 1970s, 122 GP wins, 12 TT wins
* MICK DOOHAN (Aus) 500cc world champion five times 1994-98
* MIKE HAILWOOD (GB) Nine world titles, 76 GP wins, 14 TT wins 1959-78
* EDDIE LAWSON (US) 500cc world champion
four times from
* WAYNE RAINEY (US) 500cc world champion three times 1990-92
* KENNY ROBERTS (US) 500cc world champion three times 1978-80
* FREDDIE SPENCER (US) 500cc world champion 1983, 1985; 250cc champion 1985