Angelique Kerber was leading 6-0, 1-0 when 120th-ranked Polona Hercog of Slovenia called it quits in the sultry heat of Flushing Meadows' Arthur Ashe Stadium.
Slovenia's Polona Hercog rallied from a set down to defeat French hope Mathilde Johansson and successfully defend her title at the Swedish Open here on Sunday.
Jelena Jankovic overcame problems with her serve to claim a 2-6, 6-4, 6-4 win over Melinda Czink in the second round of the Mercury Insurance Open on Thursday.
Ayumi Morita beat Slovenia's Polona Hercog 3-6, 7-6 (6), 6-1 on Sunday as Japan advanced to the Fed Cup World Group playoffs.
World No. 1 Caroline Wozniacki won for the first time in over a month, convincingly beating Polona Hercog in the New Haven Open, with Tuesday's play affected by an earthquake.
Fourth seeds Sania Mirza and Elena Vesnina's campaign ended in the doubles event of the Mercury Insurance Open following a right-hand injury to the Russian.
China's Peng Shuai and former world No. 1 Ana Ivanovic both won in straight sets on Wednesday in the second round at the Mercury Insurance Open, while Germany's Julia Goerges made an unexpected early exit.
Sania Mirza made her second consecutive first-round exit when she lost to Italian 15th seed Sara Errani in the Mercury Insurance Open, a WTA Premier event.
Vera Zvonareva converted the only two service breaks of the match, enabling her to beat veteran qualifier Jill Craybas 6-4, 7-5 on Tuesday night to progress to the round of 16 at the Mercury Insurance Open.
Roberta Vinci of Italy finished strongly for a 3-6, 6-4, 6-1 win over Serbia's Bojana Jovanovski on Monday at the Mercury Insurance Open; an event hit hard by injury withdrawals.
Polona Hercog of Slovenia reached her second straight WTA final by defeating top-seeded Flavia Pennetta of Italy 6-2, 6-2 at the Palermo Open on Saturday.
Top-seeded Flavia Pennetta defeated Tsvetana Pironkova of Bulgaria 6-2, 6-2 on Friday to reach her second semifinal of the season at the SNAI Open.
Fresh off her third title of the year, second-seeded Roberta Vinci beat Kazakh qualifier Sesil Karatantcheva 6-2, 7-5 on Tuesday in the first round of the Palermo Open.
Attempting to maintain her status as Italy's second-best player, top-seeded Flavia Pennetta beat wild card Anastassia Grymalska 6-4, 6-1 in the opening round of the Palermo Open on Monday.
Top-seeded Jelena Jankovic of Serbia reached the final of the Monterrey Open with a 6-3, 6-2 victory over eighth-seeded Polona Hercog of Slovenia on Saturday.