BEIJING -- Defending champion Victoria Azarenka was knocked out in the first round of the China Open on Monday, losing 6-4, 2-6, 6-4 to Andrea Petkovic of Germany.
The second-ranked Azarenka double-faulted 15 times and was broken five times by Petkovic, who reached the final here in 2011.
"I'm very happy with my performance," Petkovic said. "I was happy with my movement and my serve for the most part, and I managed to get a lot of balls back very deep and very strong. Parts of the match were a really, really good level - some parts I lost a bit of energy, but overall I'm very happy."
It was the second tournament in row in which Azarenka lost her first match, having been beaten by Venus Williams in Tokyo last week.
"It was an awful match and a very bad performance from me, so there's not much to say about it," Azarenka said. "It happens once, twice a year to every player, and it happened to me today."
Also Monday, Montreal's Eugenie Bouchard advanced with a 6-4, 6-1 win over Slovakia's Magdalena Rybarikova that took just an hour and five minutes.
Bouchard, ranked 36th in the world, broke Rybarikova's serve six times in the match.
She will play American Slone Stephens in the second round. Bouchard defeated Stephens at last week's Pan Pacific Open in Tokyo.
In other Canadian results, Kazakhstan's Galina Voskoboeva beat Toronto's Sharon Fichman 6-4, 6-1.
Elsewhere, eighth-seeded Jelena Jankovic rallied for a 1-6, 6-4, 6-0 win over Anastasia Pavlyuchenkova of Russia.
Former No. 1-ranked Jankovic had lost three of her four previous matches against Pavlyuchenkova and didn't start well in Beijing, but recovered to break her opponent three times in each of the second and third sets.
The 28-year-old Jankovic, who won the title here in 2008, took control of the match as her opponent struggled with her first serves and double-faulted nine times.
Jankovic's compatriots Ana Ivanovic and Bojana Jovanovski joined her in the second round with easier straight-set victories.
Ivanovic defeated Flavia Pennetta of Italy 7-6 (9), 6-1 while Jovanovski took just 77 minutes to dispose of Sorana Cirstea of Romania 6-3, 6-2.
In the doubles, wild-card entries Serena and Venus Williams wasted chances to win before losing 6-7 (3), 6-4, 11-9 in a Champions tiebreaker to Liezel Huber and Taiwan's Chan Hao-ching. Serena Williams double-faulted on match point to hand her opponents the win, and then angrily slammed her racket against the court three times before tossing it to the side.
In the men's draw, Australian Lleyton Hewitt knocked out seventh-seeded Tommy Haas of Germany 7-6 (6), 6-3 in the first round.
Australia's Bernard Tomic, Fabio Fognini of Italy and Philipp Kohlschreiber of Germany also advanced.