French fourth seed Nicolas Mahut lost 6-4 6-4 to Richard Berankis on Friday at the Los Angeles Open as the Lithuanian qualifier reached the first ATP semi-final of his career.

Mahut, who beat the No.141 in their previous meeting in Atlanta in 2011, was unable to keep a clean slate against the 22-year-old, who will face the winner from Australian sixth seed Marinko Matosevic and Michael Russell.

Russell accounted for top seed Benoit Paire of France in the second round at UCLA.

World No.66 Mahut exited in just under 90 minutes as he lost serve once per set to the eager challenger.

“It was a great match for me, we both played well,” Berankis said.

“I was lucky on some returns. Somehow I won today, I’m really happy about it.”

Berankis is the first Los Angeles qualifier in three years to get this far, following in the footsteps of Australian Carsten Ball, in 2009, a losing finalist.