Recent Wimbledon semifinalist Donna Vekic is parlaying grass-court form into clay-court success at the Paris Olympics.

The 13th-seeded Croatian saved three set points in the opening set en route to upsetting No.2 seed Coco Gauff 7-6(7), 6-2 in Tuesday's Round of 16. Vekic trailed 4-1 and 5-2 in the opening set, saving a set point on serve at 5-3, and later erased two chances for Gauff in the tiebreak to earn her second Top 10 win of the season and 14th of her career.

Vekic also earned a win over a player ranked in the world's Top 3 at the last Olympics, having defeated then-No.3 Aryna Sabakenka in Tokyo, but her win over Gauff marked a milestone: All of her previous Top 10 wins came on either hard courts or grass. 

Her win also matches the best-ever result for a Croatian woman at the Olympics, as Iva Majoli made the quarterfinals in 1996. 

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After a tight opening set that lasted more than an hour, Gauff was the first player to break serve in the second set, but ultimately lost the last five games. Vekic's second service break came in controversial fashion. At 30-40, she hit a return deep to Gauff's forehand, which the American mishit into the net. The shot was called out by the line umpire, who then immediately corrected the original call, and the point was awarded to Vekic.

The decision visibly upset Gauff, who nonetheless led 0-40 in the Croatian's subsequent service game. But Vekic escaped with a hold -- a drop shot winner and a lob winner helping the baseliner's cause -- as she won 10 of the last 12 points of the match.

In all, Vekic struck 28 winners to Gauff's nine in the upset. 

There were mixed results for the three Americans in action on the whole:

  • Eighth seed Danielle Collins ended the inspired run of unseeded Colombian Camila Osorio, 6-0, 4-6, 6-3, behind 37 winners and seven breaks of serve. After failing to capitalize on a set and a break lead, a 5-1 start in the final set was more than enough cushion for Collins to move through to the final eight.
  • But No. 11 seed Emma Navarro was unable to convert a match point in what was an eventual 6-7(7), 7-6(4), 6-1 loss to No.6 seed and Australian Open finalist Zheng Qinwen. The match lasted 3 hours and 12 minutes, the first match at the Paris Olympics to break the three-hour threshold. Navarro trailed 5-3 in the first set before winning it, and had leads of 3-1 and 5-3 in the second. She had a match point on Zheng's serve in the ninth game, and failed to serve out victory at both 5-4 and 6-5.