Jessica Pegula knocked out top seed and fellow American Coco Gauff 7-5 7-6(2) in a rain-interrupted semi-final clash and went on to beat Anna Kalinskaya 6-7(0) 6-4 7-6(3) in the final to win the Berlin Open on Sunday.

The semi-final was suspended on Saturday due to rain, with world number five Pegula leading 7-5 6-6(3-1). She wasted no time after the match resumed under a cloudy sky on Sunday, winning four of the last five points to reach the final.

Pegula lost a competitive first set to Russian Kalinskaya after both players broke the other three times each. But the American bounced back, breaking in the very first game to set up a win in the second set.

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Pegula, 30, broke Kalinskaya to take a 3-1 lead in the third set, but the Russian 25-year-old fought back with a break of her own and saved four break points in the next game to make it 4-4.

Kalinskaya was on the verge of two more breaks that would have taken her to victory but the American saved five match points to win both games and take the set into tiebreaker, where she ultimately prevailed.

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The win marked Pegula's fifth career singles title and the first on grass, days before she competes in the Wimbledon where she reached the quarterfinals last year.