World number one Simona Halep and defending champion Caroline Garcia suffered second-round defeats while Elina Svitolina and Karolina Pliskova also made early exits at the Wuhan Open on Tuesday.
Halep received treatment on her back and left thigh before succumbing 6-0 7-5 to Dominika Cibulkova in the top seed's first match since losing to Kaia Kanepi in the opening round of the US Open.
Garcia will not be repeating her success of last year in China after Katerina Siniakova consigned the fourth seed to a 3-6 7-6 (7-5) 7-6 (7-4) defeat, the qualifier saving a match point in the second set before going on to pull off a shock.
Svitolina, the sixth seed, went down 6-4 2-6 6-1 to Aryna Sabalenka, while Pliskova and Kiki Bertens were knocked out after winning the Tokyo Open and Korea Open respectively last weekend.
Madison Keys retired from her match against Angelique Kerber at 6-0 4-1 down due to a knee injury on a day which saw Caroline Wozniacki, Petra Kvitova and Garbine Muguruza reach round three.
CIBULKOVA MAKES HAMPERED HALEP SUFFER
Halep injured her back during a training hit on Sunday and the French Open champion was clearly not fully fit as she suffered the humiliation of a first-set bagel.
Cibulkova showed no mercy on the hampered Romanian, who could only muster one winner in the opening set.
Halep appeared to benefit from a couple of medical timeouts as she fought back from 2-0 down in the second to lead 4-2, but the Slovakian cut down the unforced errors to avoid a decider, sealing victory after midnight.
Cibulkova will take on Daria Kasatkina - a winner over Halep in the second round of this tournament last year - in the third round.
BATTLING SINIAKOVA HANGS IN THERE TO TOPPLE GARCIA
Garcia, who became the first player to be crowned champion in Wuhan and Beijing back-to-back last year, paid the price for not being able to put Siniakova away in the second set.
The world number four from France had the opportunity to serve out the match, but failed to do so and squandered a 3-1 lead in the third before losing a tie-break.
"It was such a long battle, I'm very happy that I won," said Siniakova, who will now go up against Muguruza. "[Garcia and I] have already played a few times and every time it's three sets. Every time I played her it was really long and tough match, so I was expecting a tough one."
SURGING SABALENKA SEES OFF SVITOLINA
Sabalenka proved just how dangerous she can be once again by claiming the scalp of Svitolina.
The unseeded Belarusian secured a seventh top-10 win of the season after giving eventual champion Naomi Osaka a big test in the fourth round of the US Open.
"I've not been counting! [her wins over players in the top 10] It's always special to beat top players. I'm so happy with this result," said Sabalenka.
PLISKOVA AND BERTENS BROUGHT BACK DOWN TO EARTH
Pliskova was on a high after beating Osaka in her homeland to win the title in Tokyo on Sunday, but the eighth seed was stunned 6-1 3-6 6-3 by new Chinese number one Wang Qiang two days later.
Bertens wrapped up her third title of the year in Korea, but Anastasia Pavlyuchenkova saw off the world number 11 with a 6-4 6-2 success.
Both Pliskova and Bertens are battling to seal spots in the season-ending WTA Finals in Singapore.
|Marcelo is an institution - Eusebio denies targeting Real Madrid left-back|
|I´d rather surround myself with people I really like - Osaka explains coach split|
|We do not have to kill Real Madrid forever - Odriozola|
|Bristol City 0 Wolves 1: Cavaleiro repeats cup heroics|
|Blackburn Rovers 0 Middlesbrough 1: Assombalonga strengthens Boro´s play-off credentials|
|Coman restricted to light training ahead of Liverpool clash|
|Solari refuses to concede LaLiga title race is over|
|Courtois: Real Madrid could not control Girona|
|Weary Kvitova reflects on ´crushing´ start to 2019|
|Umtiti in Barcelona squad to face former club Lyon|
|It´s hard to take - Maxwell laments Stars´ stunning Big Bash defeat|
|Pogba: Manchester United emulating ´Class of 92´|
|Real Madrid 1 Girona 2: Stuani and Portu seal stunning comeback|
|Boult, Mahmudullah fined by ICC|
|Neymar Senior: No chance of PSG star facing Manchester United|
|Broad expects sledging to subside in 2019 Ashes|
|Aguero targets historic quadruple|
|Scholes backs Solskjaer for Man United job|
|Finch hails ´special´ Renegades comeback|
|Sydney FC 1 Central Coast Mariners 1: Le Fondre strike averts shock defeat|
|Fox soars in Perth final to win World Super 6|
|Williams delay start to pre-season testing|
|Renegades crowned BBL champions after stunning Stars collapse|
|What we learned from NBA All-Star Saturday|
|Kaepernick´s attorney tips Patriots to make move for QB|
|Tebow: I told Murray to follow his heart|
|Mourinho created unhealthy atmosphere – Sanchez|
|Santa Cruz defends belt against Rivera|
|Opelka, Isner set ATP Tour record at New York Open|
|Diallo soars over Shaq to win Slam Dunk contest|
|WATCH: Diallo dunks over Shaquille O´Neal|
|Silver: NBA trade requests should stay behind closed doors|
|´It´s more of an aspiration´ – LeBron clears up potential NBA ownership|
|Harris wins Three-Point contest ahead of Curry|
|Thomas leads rain-delayed Genesis Open|
|Tatum wins NBA Skills Challenge with stunning half-court shot|
|Robben: Anfield is the worst stadium|
|Valverde not nervous about Messi penalties after spot-kick miss|
|Sanchez ´worried´ amid Man United struggles|
|Schoeman hat-trick sees Lions past Jaguares|
|Piatek lives to score goals - Milan striker´s brilliant double pleases Gattuso|
|Lyon will punish Barca in this form, Pique warns|
|Guardiola lauds Silva´s ´incredible´ FA Cup performance|
|Clermont hit the top, Perpignan finally win|
|Schwartzman saves match point to down Thiem in Buenos Aires|
|Leinster withstand Zebre test as Connacht claim big win|
|Antonio Brown: Roethlisberger has owner mentality and you can´t call him out|
|Pizarro becomes Bundesliga´s oldest ever goalscorer|
|Wawrinka ends 20-month wait for final to book Monfils showdown|
|Barcelona 1 Real Valladolid 0: Hit and miss as Messi gets job done|
|Atalanta 1 AC Milan 3: Two-goal Piatek lands blow in fight for fourth|
|NBA, FIBA link up to start 12-team league in Africa|
|Guardiola proud of ´incredible´ City after Newport win|
|Worst pitch I´ve played on - Manchester City hero Foden unimpressed with Newport surface|
|LeBron James, Derek Jeter lead praise for retiring Yankees legend CC Sabathia|
|Durant happy for Porzingis but guarded on his own future|
|Newport County 1 Manchester City 4: Foden nets brace as upset is averted|
|Simeone plans Griezmann, Costa, Morata trident|
|Stephen Curry reveals three-point contest bet with brother Seth|
|Celtics, Lakers, Knicks on Anthony Davis´ list, along with 26 others|
|Mertens fights back to defeat Halep for her biggest WTA title|
|Championship Review: Norwich hit four as Baggies & Blades cruise|
|Sala mourned at funeral in Argentina|
|Costa thrilled to make Atletico return at old club Rayo|
|Specman´s spectacular debut double leads Bulls in Stormers thrashing|
|Sarries pounce on Chiefs slip as Saints sink sorry Sharks|
|Griezmann overtakes Torres on Atletico Madrid´s top-scorer list|
|LeBron James reacts to Kaepernick´s settlement with NFL: I´m happy he won his suit|
|Giannis to play for Greece at FIBA Basketball World Cup|
|Next question! - Russell Westbrook on All-Star Game team-mate Joel Embiid|