Ibragimov is one of seven southpaws to become world heavyweight champion: the others being Michael Moorer, Corrie Sanders, Chris Byrd, Ruslan Chagaev, Charles Martin (boxer) and Oleksandr Usyk.

He remains one of only five former world heavyweight champions, alongside Gene Tunney, Rocky Marciano, Riddick Bowe and Nikolai Valuev to have never suffered a stoppage defeat.

Soon after he was spotted by the AIBA Vice President and Russia's top boxing official Ramazan Abacharayev, his compatriot from Dagestan, who became his trainer and mentor for a long time.

[8] After the fight, Dundee once again praised Ibragimov for his performance: "America might finally see a great white heavyweight champion for the first time in 50 years.

[6] After scoring two more first-round stoppages, Ibragimov then faced his former teammate Alexey Osokin, defeating him by a wide unanimous decision.

[12] Walton did not come out of his corner for the seventh round, prompting the referee to stop the fight and declare Ibragimov the winner by sixth-round TKO.

[15][16] Ibragimov then took a big step up in competition when he agreed to face former IBF world cruiserweight champion Al Cole on 3 March 2005.

The fight took place at the Madison Square Garden Theater and headlined the card that also featured Timur Ibragimov, former world super-featherweight champion Kevin Kelley and heavyweight contender Shannon Briggs.

Cole was coming off of a close UD loss to Hasim Rahman, and had only been stopped by Corrie Sanders and long-time cruiserweight champion Juan Carlos Gomez up to that date.

[23][6] During pre-fight press-conference, boxing promoter Sal Musumeci compared Sultan Ibragimov to Rocky Marciano, noting that they have a similar fighting style and training process.

[29] On 16 September 2005 Ibragimov faced his former sparring partner[10] and once-highly regarded prospect Friday Ahunanya at the Infinite Energy Arena in Duluth, Georgia.

[30] In attempt to narrow the round's score from 8–10 to 9-10, Ibragimov staggered Friday with a series of shots to the head and body, almost finishing Ahunanya who was saved by the bell.

The headbutt opened a cut under Ahunanya's left eye, prompting the referee to prematurely stop the fight and go to the judges' scorecards.

[33][34] Ibragimov had his next fight scheduled two months later against 6 ft 8 in Lance Whitaker (31–3–1, 26 KOs) at the Hard Rock Live in Hollywood, Florida.

After the fight, Mike Tyson came out to the ring and praised Ibragimov for his performance, stating that he considers the Russian boxer to be one of the best heavyweights in the world.

[55] Coming into the fight, Austin was on a 12-fight unbeaten streak which included draws against Lance Whitaker, Zuri Lawrence and Larry Donald and an upset TKO win over then-highly regarded prospest Jo-el Scott.

In the eleventh and twelfth, Ibragimov hurt Austin a few times with a left hook but was unable to finish him, although he won those rounds on the judges' scorecards.

[61][62] The debate over IBF's mantadory challenger spot ended when Ibragimov agreed to face Shannon Briggs for the WBO world heavyweight title.

Ibragimov claimed that one of his American trainers had warned him two months before the scheduled date that Briggs was going to pull out as he didn't want to fight against a southpaw.

This win broke the record for the quickest knockout in a main event bout in Madison Square Garden, which was previously held by Lee Savold who defeated Buddy Walker in 1948.

[66] Ibragimov eventually agreed to face Shannon Briggs for the WBO world heavyweight title in Atlantic City, New Jersey on 2 June 2007.

[74] Shortly after winning the title, Sultan Ibragimov signed the contract to face then-WBA world heavyweight champion Ruslan Chagaev in a unification showdown that would take place in Moscow on 13 October 2007.

The fight headlined the card that also featured another Russian boxer Dimitri Kirilov defending his IBF world super flyweight title against Jose Navarro.

[84] The fight began tentatively, with Ibragimov mostly staying at range and avoiding exchanges, keeping Holyfield at bay with fast combinations.

Ultimately, the fight went full twelve rounds, with Ibragimov being declared the winner by unanimous decision, successfully defending his WBO world heavyweight title.

[91] By the end of October 2007, Ibragimov started negotiations with then-IBF world heavyweight champion Wladimir Klitschko about the unification showdown in the near future.

[92][93] On 20 November, Klitschko and Ibragimov officially signed the contract for their unification clash to take place on 23 February 2008 at Madison Square Garden.

[97][98] In the pre-fight prediction, a vast majority of Ukrainian, Russian and American observers expected Ibragimov to lose by either stoppage or unanimous decision.

By the end of the opening round, Klitschko became more active with his jab, while Ibragimov unsuccessfully tried to catch Wladimir with a series of right and left hooks.

By the third round, Klitschko took control of the center of the ring, keeping Ibragimov at the end of his left jab and occasionally throwing straight rights as well.