Holyfield (left) clashes with Ibragimov in Moscow

Holyfield lost a unanimous points verdict in Moscow, the judges scoring the fight 118-110, 117-111 and 117-111.

The 44-year-old was unable to match Ibragimov's counter-punching.

But Holyfield insisted: "The important thing is I showed improvement and adjustment. He got the decision and I have to go back to the drawing board."

606: DEBATE Where does Holyfield go from here?

Holyfield, who last held a version of the heavyweight title in 2000, was wobbled by Ibragimov in the seventh round and again in the 10th.

The veteran's record is now 42-9-2, while Ibragimov improves to 22-0-1.

Holyfield was aiming to upset the odds and also become the second-oldest ever heavyweight world champion after fellow American George Foreman.