Former UFC heavyweight champion Tim Sylvia was apparently TKO'd by former WBO heavyweight world champion boxer Ray Mercer in the opening seconds of their mixed martial arts bout in Birmingham, Ala., on Saturday night., which carried live coverage of the Adrenaline 3 event, first reported the result. It was later confirmed by

"Tim Sylvia threw one kick then Mercer unloaded a right that connected on Sylvia and he tumbled like a 500-pound tree in the woods. Sylvia fell over and it seemed like it was in slow motion," reported

As of late Saturday night, was unable to independently confirm the result. But, if accurate, this is a devastating blow to Sylvia, who is scheduled to face Paul Buentello at Affliction 3 on Aug. 1 in Anaheim, Calif.

The loss would put Sylvia's career mark at a still respectable 24-6, but would add up to four losses in his last five bouts, including his three most recent fights. His other three losses were to Randy Couture, Antonio Rodrigo Nogueira and Fedor Emelianenko -- all top competitors. But a loss to Mercer, whose only other MMA experience was an exhibition bout loss by submission to Kevin "Kimbo Slice" Ferguson, will be a bitter pill for the former champion to swallow.

Sylvia and Mercer had originally agreed to a six-round boxing bout in the cage, but the New Jersey State Athletic Control Board was unwilling to sanction the fight. Adrenaline MMA promoter Monte Cox then moved the bout to Alabama, only to be informed a few days before the scheduled fight that it was illegal because it wasn't being sanctioned by a U.S. commission. Sylvia and Mercer, wanting the bout to continue, then agreed to fight under mixed martial arts rules.

In other notable action at Adrenaline 3, Pride and UFC veteran Jeremy Horn got back on the winning track by submitting Chris Davis with a rear naked choke in the opening round. The action marks Horn's first bout outside of the UFC after a three-fight skid in the Octagon.

Also fighting for the first time since his UFC exit, Rich Clementi pushed his back-to-back losses into the past with a side choke submission of Sasuke Zapata.

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