RIYADH — Oleksandr Usyk has been shorter, lighter and older than all of his opponents since he moved up to the heavyweight division.

Usyk's heart and skill, though, are enormous, and he overcame a major size disadvantage against Tyson Fury to become the world's first undisputed heavyweight boxing champion in 24 years.

Usyk defeated Fury by split decision on Sunday, knocking down his hulking opponent in the ninth round and eventually earning a narrow win on two scorecards. The 37-year-old Ukrainian is the first heavyweight to hold every major title belt since Lennox Lewis.

Usyk (22-0) added Fury's WBC title to his own WBA, IBF and WBO belts with a spectacular late-round rally in a back-and-forth matchup between two previously unbeaten champions from a strong era of heavyweight boxing.

Two judges favored Usyk, 115-112 and 114-113, while the third gave it to Fury, 114-113.

"It's a great time. It's a great day," said Usyk, who is 15.24 centimeters shorter than Fury and weighed in 13.61 kilograms lighter this week.

Usyk started quickly, but then had to survive while the confident, charismatic Fury dominated the middle rounds. Usyk surged in the final rounds, just as the Olympic gold medalist has done so many times in his career, taking control with a dominant eighth and nearly stopping Fury in the ninth.

Usyk hurt 206-cm tall Fury (34-1-1) with a left hand, and eventually sent him sprawling into a corner in the final seconds of the round, getting credit for a knockdown right before Fury was saved by the bell. Fury struggled to mount a consistent attack after that, and the knockdown turned out to be the decisive factor in the decision.

"Thank you so much to my team," Usyk said while fighting back tears in the ring. "It's a big opportunity for me, for my family, for my country."

Fury kissed Usyk on the head after the final bell, and Usyk hugged Fury several moments after the decision was read. Fury also said he wants the rematch in October.