Twelve months ago Roger Federer played in a Wimbledon final which amounted to sporting perfection encapsulated in five sets.

He fell two sets behind but drew on reserves of mental strength to force a decider. The trouble was, he lost it. And Federer had not been beaten at the All England Club since he was thrashed by Mario Ancic in the first round in 2002.

Defeat at Wimbledon had become an alien concept for the maestro. But after five titles, Federer had to cope with losing to a better player, namely Rafael Nadal, the man he had beaten in the two previous finals.

It might have crushed him.

Not only did defeat cost him his prized status as Wimbledon champion, but it also positioned Nadal as the superior player on all surfaces, and just weeks later the world rankings reflected that, with Federer demoted to second place behind the Spaniard.

No wonder Federer sounded so depressed.

"Later on in life I'll think it was a great match to be part of but it doesn't feel so good now," Federer said.

He explained: "In tennis unfortunately there have to be winners and losers, there are no draws. But it was probably my hardest loss by far. It doesn't get much harder than this."

The "winners and losers" system had served him well at Wimbledon from 2003 to 2007.

Considering Federer was at a low ebb, it says everything for his character that tomorrow he can secure his third grand slam title since that harrowing defeat to Nadal.

Victory over Andy Roddick will hand him a record 15th slam, nudging Federer ahead of Pete Sampras whose total he matched with his triumph at the French Open last month.

It was in Paris that Federer completed the career Grand Slam of all four majors, which is a feat Sampras fell a Roland Garros trophy - a 'Coupe des Mousquetaires' - short of achieving.

If such issues were not subjective and could be determined simply by statistics, Federer would be officially crowned the greatest of all-time with victory on Sunday. Some will make a case for Rod Laver, but many of the sport's biggest names already acclaim Federer as the best. The fact he has reached 21 consecutive grand slam semi-finals is a significant factor.

Nevertheless, when Federer lost to Nadal at Wimbledon last year, he was on 12 grand slam titles, and it was not hard to envisage him finishing his career on that mark. Great, but not the greatest, not even on paper.

He suffered a post-Wimbledon dip, losing early in two Masters Series events before being upset by James Blake in the quarter-finals at the Olympics.

However the Federer aura was restored in New York in September, where he dashed Andy Murray's hopes of a first grand slam by overwhelming the Briton in the US Open final. Nadal had slumped to Murray in the semi-finals.

He added titles in Madrid and Basle, his home town, so in January headed to Melbourne seeking slam number 14.

But Nadal defied Federer in another exhilarating five-set final.

Federer was reduced to tears, saying during an emotional post-match speech: "God, this is killing me."

No doubt. Andre Agassi later suggested Nadal could win all four majors in 2009, and it was hard to contest that. The Melbourne victory was a fifth in succession for Nadal against Federer.

Federer married former tennis professional Mirka Vavrinec in April of this year, and will become a father soon.

And in May he hit a hot streak on clay, landing the Madrid Masters Series title before heading to Paris for the French Open. When Robin Soderling eliminated Nadal, who was seeking a fifth successive Roland Garros title, the door opened for Federer.

He outclassed Soderling in straight sets in the final, becoming only the sixth man to achieve the career Grand Slam - after Fred Perry, Don Budge, Rod Laver, Roy Emerson and Agassi.

"It ends the discussion of where he fits in the history of the game," said Agassi, whose prediction of a Nadal clean sweep proved hasty.

"This is going to mean so much to him, to have that hole filled. I think it will change his life."

The absence of the injured Nadal from Wimbledon this year has denied Federer the chance to exact revenge for last year.

But given the evidence of the first 12 days of the Championships, there is every chance 27-year-old Federer would have swatted away the Spaniard.

He has dropped just one set so far, on a tie-break to Philipp Kohlschreiber.

Watching Federer on Centre Court is one of sport's thrilling experiences. The elegance of his game, and the way he makes it look effortless when it can only be anything but, defines the man. Everything falls into place for Federer on Centre, where he won his first slam six years ago.

And so to tomorrow.

"It's a great opportunity to get into the history books," Federer said.

Victory could be his sweetest yet.