IRVINE — Just about the time Darrin Van Horn got loose, his International Boxing Federation super middleweight title bout against top-ranked challenger John Jarvis was over.
Van Horn, the 22-year-old champion, floored Jarvis with an overhand right at 1:11 of the third round before about 1,000 at the Bren Center.
"I was struggling to that point," Van Horn said. "I had hit him a few times, but I wasn't smooth and I could feel it. I tried to measure it so that he would hit me a few times, but not hurt me. Once I get hit, I usually get going."
Neither fighter looked sharp in the first round, but Van Horn was more active and won the round.
In the second round, Jarvis, from Richmond, Va., scored twice on short rights and seemed ready to make a fight of it.
There was one flurry early in the third round in which each fighter landed a combination. They then danced around the center of the ring until Jarvis stepped in to begin an exchange.
Jarvis, 34, started a long right, but Van Horn was quicker, landing a right to the chin of Jarvis, who went down.
"I just threw the punch and was lucky he was coming forward into it," said Van Horn, who improved to 47-2 with 27 knockouts.
Jarvis didn't stir until referee Lou Moret had counted to six and didn't start to rise until Moret was at nine. Jarvis missed beating the count by one.
"I guess he caught me before I caught him," Jarvis said. "He hit me with a good shot. I don't agree with the count, but what can you do? It seems like when he got to six, he was counting for speed. I told him that I was all right, but it was too late. I thought I could have covered the rest of the round and gone on with the fight."
Van Horn earned $80,000 for defending the title he won in May with an 11th-round knockout of Lindell Holmes. Jarvis (22-3), earned $25,000.
"I'm going to take about a month off now," said Van Horn, a student at the University of Kentucky. "I've knocked out the champion and the No. 1 challenger, so I guess I'll keep working my way down the line."
Actor Mickey Rourke was featured on the undercard, fighting former Olympic gold medalist Frank Tate in a three-round exhibition.
Both fighters wore protective head gear and only a few solid punches landed. Among the spectators was former heavyweight champion Mike Tyson, who posed for a few pictures and left soon after the exhibition.
Some of the crowd encouraged Tate to knock down Rourke, but Tate was content to throw jabs at Rourke's chin.
Tate charged Rourke to start the third round and gave a display of his quickness, then reverted to a slow pace. After the bell, the pair hugged. Rourke thanked Tate for taking part and left the arena.
Cash McCallum (2-0-1) of Irvine scored a second-round knockout against Jaime Mungia (2-4) of Mexico on the undercard.