Keita Obara fell to a second-round TKO to hard-punching Russian champion Eduard Troyanovsky on Friday in his first IBF light welterweight title bout.
The third-ranked Obara, 29, got off to a subdued start in the first round and was overwhelmed by his 36-year-old counterpart in the second, faltering on a straight right and a left hook before getting knocked out of the ring with a flurry of blows on the ropes.
The damage was visible even after he climbed back on to the ring, and the referee intervened to stop the bout as Obara was quickly set upon by the Russian.
"I was in panic (after falling from the ring). I was desperate to somehow climb back in," said Obara. "I hadn't received such telling blows since my debut bout."
Obara, looking tight from the start, had to deal with the thunderous support from the home crowd as Troyanovsky began landing punches clinically and cruised to his second title defense, improving to 25-0 with 22 knockouts in career.
"I feel miserable, I had prepared to test many things (in the bout) but the champion was strong," said Obara, who is 16-2 with 15 KOs and a draw. "I had no experience being knocked from the ring. He was a class above both with his attacking and defense."
The last Japanese belt holder in a division deep with talent from around the world was Akinobu Hiranaka back in 1992, and Obara was eager to make the most of the lessons from his thumping.
"It's really a good thing to fight in the ring," he said with a smile. "I'll be taking this positively."