Sanjeev Shetty BBC Sport Online

Being the best at what you do is not easy and sacrifices often have to be made.

Lennox Lewis has proved over the years that he is willing and able to do whatever it takes to be the best heavyweight in the world.

In 1994, after being knocked out by Oliver McCall in two rounds, he changed his trainer and regained his title against the man who knocked him out.

After being held to a controversial draw by Evander Holyfield in 1999, he requested an immediate rematch which he won to become the undisputed champion.

And when Hasim Rahman embarrassed him last year, he ignored calls to retire, dedicated himself to training and knocked out the brash American in four rounds.

On the receiving end against Oliver McCall

Along the way, he has had to answer questions about his style, his nationality and even his sexuality.

But no one can question his right to be called world heavyweight champion - now more than ever following his comprehensive win over Mike Tyson.

The Lewis story began in September 1965, when his mother Violet gave birth to a son she christened Lennox Claudius.

A difficult childhood saw him leave his birthplace of London and move to Canada.

After trying out a number of sports with success, Lewis settled on boxing, twice competing at the Olympic Games.

He lost to American Tyrell Biggs in the quarter-finals in Los Angeles in 1984 before capturing the gold in 1988 with a stoppage of future heavyweight champion Riddick Bowe.

After receiving a host of offers from major promoters, Lewis signed a deal with London-based Frank Maloney.

Flooring Tommy Morrison

He wanted to be marketed as a British fighter, despite having represented Canada at the Olympics, with tough American John Davenport as his trainer.

Within four years, Lewis had established himself as a top contender with British, Commonwealth and European title victories.

Ultimately he was matched with Canadian Ruddock in October 1992, with the winner the top contender for the heavyweight title.

A slight underdog, Lewis destroyed the highly-rated Ruddock in two rounds to set up a long-awaited rematch with Bowe, who had defeated Holyfield for the undisputed title.

But Bowe refused to sign for the fight, and famously threw his World Boxing Council belt in the bin.

Proclaimed the WBC champion after Bowe's action, Lewis took his show on the road.

With another American, Pepe Correa, now in his corner, he made three successful defences of his title, including a seventh-round knockout of Frank Bruno.

Hammering another American, Shannon Briggs

But each win showed deficiencies in his style and, in September 1994, little-known American Oliver McCall stopped him in the second round with a perfect right hand.

That defeat, which had seemed unlikely after Lewis had looked so devastating against Ruddock, was the cue for drastic changes.

Veteran trainer Emmanuel Steward was brought in to replace Correa, and Lewis' training was moved almost exclusively to America.

The road back to the title was not easy, as Lewis' defeat at the hands of McCall allowed American boxing writers the chance to christen him as yet another "horizontal" British heavyweight hope.

But wins over contenders Tommy Morrison and Ray Mercer put him back into the frame and, when the WBC crown was vacated by Tyson in 1996, Lewis faced McCall for the chance to win his title back.

Hammering another American, Shannon Briggs

In January of the following year, Lewis achieved revenge for his only loss with a fifth round stoppage.

It later emerged that the American had suffered a nervous breakdown in the ring, due to his problems in overcoming drug and alcohol addiction.

Further wins over the likes of Andrew Golota and Shannon Briggs set up a unification match against Holyfield.

That meeting, in March 1999, will live long in boxing infamy, with Lewis forced to settle for a draw after appearing to outpoint his veteran opponent comfortably.

The decision of the judges, one of whom was British, incensed the watching world, with an immediate rematch ordered.

Eight months later the rematch saw Lewis awarded a unanimous decision, to become the first British heavyweight to win a unified heavyweight title since Fitzsimmons in the latter stages of the 19th century.

Beating Holyfield, this time according to the judges

His three defences in 2000, against Grant, Francois Botha and Tua displayed the kind of authority that has sometimes been missing in his 11-year professional career.

But the defeat at the hands of Rahman prompted critics to question his credibility as a real champion.

Lewis avenged the loss in November of 2001, knocking out Rahman in four rounds in utterly compelling fashion.

It was inevitable that talk of a clash with former champion Mike Tyson would emerge.

After months of speculation and bickering behind the scenes the fight was finally given the go-ahead.

And when it came to the crunch Lewis proved to the world that he was up to the task that many thought was beyond him.

It would be a harsh person that would deny Lewis his place in boxing's hall of fame.