Looking back at the biggest fights of Amir Khan's career

— -- Former Great Britain Olympic medalist Amir Khan will challenge middleweight champion Canelo Alvarez on Saturday at the T-Mobile Arena in Las Vegas.

Khan (31-3, 19 KOs), a former unified junior welterweight titlist, will move up from 147 pounds to face Alvarez (46-1-1, 32 KOs) at a catchweight of 155 pounds.

Despite great speed, explosive combinations and plenty of heart, Khan knows he is a big underdog against Alvarez -- but he has nothing to lose and much to gain. If Khan puts on an impressive performance, even in defeat, he will walk away with a much healthier bank account and big options for the future.

Let's look back at the best performances of Khan's career:

5. Khan's coronation against Andriy Kotelnik (July 18, 2009)

Five years had passed since Khan won the lightweight silver medal at the 2004 Athens Olympics, and there were serious doubts about whether he had the ability to bounce back from a stunning 2008 first-round knockout loss to Breidis Prescott. Instead, Khan put on an impressive show against Kotelnik, who was fresh off a victory over Marcos Maidana. Khan, who captured Kotelnik's 140-pound title, relied on his speed -- using his power only when it mattered most -- to claim a wide decision.

4. Khan proves his quality vs. Marco Antonio Barrera (March 14, 2009)

Six months after being knocked out by Prescott in the first round, Khan took the risk of facing the aging -- but still dangerous -- Barrera, a three-time champion. The fight was stopped in the fifth round after Barrera, 35, suffered a heavy cut, but Khan proved that his speed would be a nightmare for anyone. It marked the first big win of Khan's professional boxing career.

3. Lightning speed in victory over Devon Alexander (Dec. 13, 2014)

Facing Alexander, a southpaw and former two-division titlist, is no easy task. But thanks to Khan's speed, foot movement and combinations, he was able to nullify Alexander and stay out of danger for the majority of the fight. It wasn't exactly a war but rather a great exhibition of speed by Khan, who nearly pitched a shutout on all three scorecards.

2. Brilliant stoppage of Paulie Malignaggi (May 15, 2010)

Only three men had beaten Malignaggi, a former two-division titlist, before he faced Khan -- and all of them had been top-shelf opponents: Miguel Cotto, Ricky Hatton and (via controversial decision) Juan Díaz. Against Khan, Malignaggi was stopped in the 11th round, as his elusive style proved unable to handle the quick hands of the British fighter, who burst onto the scene in his U.S. debut, headlining the Theater at Madison Square Garden in New York.

1. Khan shows guts against Maidana (Dec. 11, 2010)

Khan's junior welterweight title defense against Maidana, held at Mandalay Bay in Las Vegas, will always be a memorable date in his career. Khan dropped Maidana in the first round after a hook to the liver and kept his opponent at bay with speed. Khan was forced to showcase his grit in the later rounds and never gave up, even when he was close to being knocked down himself. It was one of the best fights of the year and propelled Khan into the public eye, showing his pride, guts and skill against a typically brave and powerful Maidana.