World No 2 Caroline Wozniacki produced an erratic performance to fall 6-2, 6-3 to Alona Bondarenko in the second round of the Madrid Open on Tuesday.
Ukrainian Bondarenko was on inspired form against the 19-year-old Dane, losing finalist at last year's US Open, and forced five breaks of serve with her powerful groundstrokes.
Wozniacki, who is recovering from an ankle injury and had her right foot strapped up, became increasingly frustrated and her father and coach Piotr's vigorous encouragement from courtside was not enough to stop the rot as Bondarenko made winner after winner.
The unseeded 25-year-old wrapped up the win on her second match point after one hour and 20 minutes.
Second seed Wozniacki said the ankle was improving all the time and her priority now was to get fully fit for the French Open, which starts in Paris later this month.
"I'm never happy to lose a match," she said.
"I'll be back on the practice courts tomorrow and work my butt off and hopefully it'll come back."
She added she will next head to Poland, the country of her parents' birth, for next week's clay event in Warsaw, where she hoped to get plenty of match practice.
"If you've twisted your ankle a few times like I have you need to get your confidence back," she said.
"It's especially important on clay where you need to slide and the surface is uneven. I really think I am going to be okay for the French Open."
GOOD PREPARATION
Bondarenko, who won the second singles title of her career at Hobart in January, said a week's practice at home had been good preparation for Madrid.
"I think she didn't have her best day today," Bondarenko said.
"I know her game well and always she plays without mistakes but today there were a lot of mistakes."
In other second-round matches, the ninth, 12th and 14th seeds all fell to unseeded opponents.
Patty Schnyder came from a set down to beat number nine Agnieszka Radwanska 3-6, 6-4, 6-4, Anabel Medina Garrigues thrashed No 12 Marion Bartoli 6-2, 6-0 and Andrea Petkovic ousted No 14 Flavia Pennetta 7-6, 6-3.
Eighth seed Samantha Stosur ended Maria Jose Martinez Sanchez hopes of a second straight title after her success in Rome last week, winning 7-6, 6-4.
