Indian Wells - Unseeded Borna Coric defeated hard-serving Kevin Anderson 2-6, 6-4, 7-6 (7/3) to post his first career win over the South African and advance to the Indian Wells semi-finals.
The 21-year-old Coric survived a 16 ace performance by Anderson as he improved to 10-3 on the season and punched his ticket to his first semi at the hardcourt tournament in the California desert.
"It has been a fantastic week," Coric said.
Coric had lost three straight matches to world No 9 Anderson, including one in the round of 32 at last year's US Open. Anderson went on to his first career Grand Slam final where he lost to Rafael Nadal.
"I know I lost to him three times in the past, I never played good against him," Coric said. "I just needed to serve better and taking more risks."
Coric won 69 percent of his second serve points and broke Anderson's serve twice in Thursday's two hour, 22 minute match on the main stadium court.
The 31-year old Anderson won the first set but failed to muster much of a challenge in the third set tiebreaker, losing five of the final six points.
Coric iced the victory on the first match point when Anderson hit a shot long.
Coric is ranked 49th in the world and certain to improve after his Indian Wells run.
The crafty Croatian is having a productive season after going through a lot of upheaval in 2017 when he replaced his coach, agent and trainer.
He celebrated Thursday's win with a fist pump and a scream while looking over to his current team.
"I was in the same place for the last three years. I think I can be better than that," he said.
"Obviously I needed to change something. And I cannot change myself. I cannot fire myself. I just decided to change my whole team. I had that opportunity and I thought it is a very clever move."
He now has Riccardo Piatti as a coach.
"We talked a lot in December and looked at the things I needed to do better, my attacking game and my return," Coric said.
Heading into the match, Anderson led the tournament in aces with 55.
Anderson dropped to 14-4 on the season as he was looking for his second title of 2018, having defeated Sam Querrey in the final of the New York Open.
Earlier this month he also reached the Mexican Open final but lost to Argentina's Juan Martin Del Potro.
Results on Thursday from the ninth day of the ATP and WTA Indian Wells tournament:
Daria Kasatkina (RUS x20) bt Angelique Kerber (GER x10) 6-0, 6-2
Venus Williams (USA x8) bt Carla Suarez Navarro (ESP x27) 6-3, 6-2
Roger Federer (SUI x1) bt Chung Hyeon (KOR x23) 7-5, 6-1
Borna Coric (CRO) bt Kevin Anderson (RSA x7) 2-6, 6-4, 7-6 (7/3)