Britain's Luke Campbell lost his WBA lightweight title fight against Jorge Linares on a split decision.
It was the toughest test since turning professional for 29-year-old Campbell, who won Olympic gold at London 2012.
He recovered after being knocked down in the second round, but Linares, 32, used his experience to see out the win.
Scot Victor Loughlin had Campbell winning 115-113, but the other two judges gave it to the Venezuelan with scores of 115-112 and 114-113.
The defeat in Inglewood, California is the second of Campbell's career after his shock loss to Yvan Mendy in 2015, while Linares - whose past two fights were points victories over Britain's Anthony Crolla - extended his record to 43 wins.
"He's a great champion but I thought I outclassed him," said Campbell.
"No-one can ever doubt my heart. I got off to a rocky start, he hit me with a nice clean shot in the second round, caught me on the eye and cut it. I wasn't dazed or anything like that, just a nice shot that put me on my back.
"From then I had double-vision in one eye for the rest of the fight.
"I thought I won the fight. I didn't think he was landing any shots whatsoever and I was catching him with all the clean shots."