Petra Kvitova, of the Czech Republic, returns a shot to Garbine Muguruza, of Spain, during the third round of the U.S. Open tennis championships on Sept.3, 2022, in New York. (EDUARDO MUNOZ ALVAREZ / AP)

NEW YORK - Czech Petra Kvitova sent across 14 aces to down Spanish ninth seed Garbine Muguruza 5-7 6-3 7-6(10) in a thrilling third-round duel at the US Open Saturday.

Kvitova was in good form headed into Flushing Meadows after reaching the Cincinnati final and reiterated her claim as one of tennis' great fighters when she saved match point twice late in the third set to push the affair into the tiebreak.

Petra Kvitova had the crowd squarely on her side in her 15th appearance in the Flushing Meadows main draw but it will be a different story when she faces home hope Jessica Pegula next, after the American reached the quarter-finals at the Australian Open and Roland-Garros

The twice Wimbledon champion said she was inspired by 23-times Grand Slam winner Serena Williams, whose emotional farewell to the US Open with a gritty, third-round loss to Ajla Tomljanovic on Friday overshadowed the entire tournament.

"I watched Serena last night and it was amazing how she was saving those match points, so I tried to do the same," said Kvitova.

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Muguruza, who suffered first-round exits from Wimbledon and Roland-Garros before pulling out of August's Silicon Valley Classic with an injury, was not at her fighting best as she sent over 21 winners to 43 from her opponent across the match.

The twice Grand Slam champion Muguruza pulled out every weapon in her arsenal to defend three match points in the 22-point tiebreak but was forced to endure another heartache this year when she whacked the ball into the net on the final play.

Garbine Muguruza, of Spain, returns a shot to Petra Kvitova, of the Czech Republic, during the third round of the US Open tennis championships on Sept 3, 2022, in New York. (EDUARDO MUNOZ ALVAREZ / AP)

"I'm proud of my fighting spirit. I have had some tough losses this year, but definitely this one makes me feel like my fighting spirit was there, my tennis was there," said Muguruza.

Kvitova had the crowd squarely on her side in her 15th appearance in the Flushing Meadows main draw but it will be a different story when she faces home hope Jessica Pegula next, after the American reached the quarter-finals at the Australian Open and Roland-Garros.

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"I will face Jessica and the crowd, for sure," she told reporters.

"She is really playing very solid game. Not only here but even whole season she was really going deep in these tournaments."