Jessica Pegula battled back from a deficit in the deciding set to knock out defending champion Iga Swiatek, 7-5, 4-6, 6-4, and advance to the Cincinnati Open final Saturday. 

The world No. 3 American needed two hours and 47 minutes to overcome the six-time Grand Slam champion in a match filled with momentum swings, service breaks and a rain delay. 

Pegula claimed a chaotic opening set, 7-5, before Swiatek responded by taking the second, 6-4, to force a decider.

Swiatek appeared to gain control after moving a break ahead in the third set, but Pegula fought back. At 4-4, the American eventually secured the decisive break after Swiatek saved three break points before double-faulting on the fourth. Pegula then served out the victory. 

The result ended Swiatek’s title defense and halted her 10-match winning streak on the North American hard courts. 

It also gave Pegula the 300th match victory of her career and sent her into her ninth WTA 1000 final. She is seeking a 12th career singles title. 

Pegula will face either fellow American Coco Gauff or unseeded Czech Sara Bejlek in the championship match.