Cincinnati, USA: Dutch challenger Kiki Bertens profited from a third-set collapse by Simona Halep to score the biggest win of her career Sunday, beating the world number one 2-6, 7-6 (8/6), 6-2 in the Cincinnati WTA final.
"This is the best day of my career, winning on a surface that you didn't really like. That's a great feeling," Bertens said.
"I'm just so proud, and it's such a great feeling to hold the trophy at the end of the week."
Halep, who claimed the Montreal title a week ago and came into the final on a nine-match winning streak, ran out of reserves and was unable to stop the mounting Bertens momentum.
"I’ve lost three finals here, but maybe I will able to win one at this tournament because I love to play here," said Halep, who fell to Serena Williams in the 2015 final of the hardcourt US Open tuneup and to Garbine Muguruza in the title match last year.
"I had match ball, so I was there," Helep said. "I didn't take my chance. In the third set I was empty and I couldn't fight anymore."
The upset took just over two hours and marked the 10th time this season that 17th-ranked Bertens has defeated a top 10 opponent.
"It was such a tough match, and after winning that second set I knew, anything is still possible -- just keep on going," said Bertens, who claimed a sixth career WTA title.
"Winning a title like this, my first hard court title, and against number one of the world, getting my career high on Monday ... it's just coming everything together, I guess," she added.
Bertens saved a Halep match point in the second-set tiebreaker to stay alive.
"I'm a little bit upset because I couldn't manage better today, but that's it. I'm like this, and I have to work more," Helep said.
Halep had looked like ending a quick afternoon with a victory after breaking Bertens twice to sweep the first set.
But the 26-year-old Dutchwoman, who had considered retiring last season due to poor results, began to turn the tide in the second as she broke for a 3-1 lead.
Halep got that break back in the eighth game to make it 4-all, and took tighter control in the tiebreaker.
But Bertens won four games in the decider to take a 4-2 lead and quickly seized the set seconds after saving the match point.