The fourth-ranked Clijsters has not played since winning the US Open in September because of a foot injury, but she won the first eight points without reply on her way to a comfortable win on Wednesday.
Jankovic said after her opening match — a defeat by Vera Zvonareva — that she was struggling with illness. The Serb took a 2-1 lead in the second set, but Clijsters came back to make it 4-2 before closing out the match when Jankovic double-faulted.
In Wednesday’s opening match, Zvonareva claimed her second win of the White Group by beating Victoria Azarenka 7-6 (4), 6-4.
In contrast to her straightforward victory over ailing Serb Jelena Jankovic, the Russian was pushed hard by Azarenka, who arrived in the Qatari capital fresh from capturing her second title of the year in Moscow.
After an uninspired opening, punctuated by a bizarre breakdancing interlude on the purple-colored court following the second changeover, Zvonareva’s superior groundstrokes began to tell as Azarenka became increasingly erratic and emotional.
The 21-year-old from Belarus squandered a glorious chance to break in the eighth game, letting out a deafening shriek of frustration.
The first set went to a tiebreak, Zvonareva breaking immediately to jump out to an early lead and despite struggling on her own serve she wrapped it up 7-4.
In the second set, Zvonareva had the pony-tailed Azarenka on the back foot, arrowing deep backhands to the corners and finding her target with sickening consistency.
Despite playing a day earlier, the Russian was the one dictating the pace, pushing Azarenka around the court and forcing her into a string of unforced errors.
At 5-4 down, Azarenka saved two match points but she netted a weak forehand on the third to hand victory to the Russian.
Melzer into Vienna quarters
In Vienna, defending champion Jurgen Melzer defeated Lukasz Kubot of Poland 7-6 (3), 7-6 (2) to reach the quarterfinals of the Bank Austria Trophy on Wednesday.
Melzer, top-seeded on tour for the first time, had an early break but then lost four games in a row to go 5-3 down. He saved a set point when Kubot served at 5-4, and took the opening set on his first chance in the tiebreaker.
Melzer went 4-1 up in the second but again needed a tiebreaker, and converted his first match point when Kubot netted a return.
“It was far from easy as he took many risks,” Melzer said of Kubot, who served 13 aces but also nine double faults. “I was more consistent and tried to stick to my own game.”
Melzer, at a career-high 12th ranking, said winning the first set from 5-3 down was key.
“I was very glad to take that opener,” the Austrian said. “From then on, I knew I had to rely on my own strengths.”
In the quarterfinals, Melzer will take on either seventh-seeded Philipp Kohlschreiber or fellow German Tobias Kamke.
In first-round play, Bjorn Phau had a surprise 6-2, 6-4 win over fellow German Florian Mayer, who lost his third career final to Roger Federer in Stockholm on Sunday.
Phau next plays fourth-seeded Marcos Baghdatis, who had a bye in the first round.
Isner reaches quarterfinals
In Montpellier, France, fifth-seeded John Isner of the United States moved to 999 aces for the season as he edged out French qualifier Adrian Mannarino 7-6 (5), 6-7 (5), 6-3 in the second round of the Open Sud de France on Wednesday.
The 2.09-meter (6-foot-9) Isner sent down 27 aces in a 2 hours, 11 minutes win on the indoor hard court and converted his sole break point to advance, while Mannarino wasted his six break chances.
Isner will next play either No. 3 Gael Monfils of France or Steve Darcis of Belgium for a semifinal spot.
Jarkko Nieminen of Finland rallied from one set down to claim his first victory in six matches over Frenchman Florent Serra and reach the second round with a 6-7 (4), 7-5, 6-1 win.
Defending champ Stakhovsky ousted
In St. Petersburg, Russia, defending champion Sergiy Stakhovsky was eliminated from the St. Petersburg Open on Wednesday, losing to Benjamin Becker of Germany 6-4, 5-7, 6-4 in the first round.
After losing the first set, the 37th-ranked Ukrainian saved a match point and broke Becker in the 12th game of the second set to stay in the match. But the 57th-ranked Becker never gave Stakhovsky a chance in the third set, losing only six points on his serve.
“It’s always difficult to come and defend your title,” Stakhovsky said. “I could have won the match, but the chances I had, I didn’t use them properly and the match was over. I cannot say that I played badly, but he left me no chances after a break in the third set.”
Also, fourth-seeded Yen-hsun Lu of Taiwan defeated Potito Starace of Italy 6-2, 6-2. Rainer Schuettler stopped fifth-seeded Viktor Troicki 6-3, 4-6, 6-3.
Alexandr Dolgopolov defeated Fabio Fognini 7-6 (5), 6-4.
