WUHAN, China (AFP) - World number one Simona Halep, playing her first match since an early exit from the US Open last month, was toppled by Dominika Cibulkova at the Wuhan Open in China on Tuesday (Sept 25).
The sparse crowd watching the late-night clash was stunned as the decidedly off-colour Halep failed to win a single game against the hard-hitting Cibulkova in the first set.
The struggling Romanian star then put up a strong fight in the second set, breaking the 31st-ranked Slovakian's serve three times before succumbing 7-5.
Halep, whose place at the top of the WTA rankings could be under threat after Tuesday's defeat, had been working on recovering her strength and focus after a shock exit in the opening round of the US Open last month.
But the Wuhan top seed appeared to have failed to recover from an injury she suffered during a practice session on Sunday. She needed treatment several times during the match, and was cheered every time she ran to the baseline to resume play.
Halep was the biggest casualty on a day of upsets at the 2018 Wuhan Open, a $2.7-million tournament which features nine of the world's top 10.
World number four Caroline Garcia was knocked out by qualifier Katerina Siniakova in a gruelling clash, with the second and third sets were decided by tie-breakers.
Local favourite Wang Qiang ousted the 7th-ranked Karolina Pliskova 6-1, 3-6, 6-3 in another thriller while 6th-ranked Elina Svitolina also failed to impress, going down 6-4, 2-6, 6-1 to Aryna Sabalenka.
It was a much happier day for Wimbledon champion Angelique Kerber and Australian Open holder Caroline Wozniacki, both advancing comfortably to the next round.
Wozniacki, who received a first-round bye, was barely troubled by the 61st-ranked Swede Rebecca Peterson, winning 6-4, 6-1 to set up a third-round clash with Olympic champion Monica Puig, who romped past Aliaksandra Sasnovich 6-2, 6-2.
World number two Wozniacki is looking for a good run in Wuhan to secure a return to the WTA Finals, which she won last year.
The 3rd-ranked Kerber has already qualified for the Finals, and advanced after a knee injury forced her American opponent Madison Keys to retire.
The German looked set for a big win over the 2017 US Open semi-finalist and was leading 6-0, 4-1 when Keys could not continue.
Kerber could return to world number one with a successful end to the season, especially after Halep's wobble in Wuhan.