Venus Williams' bid to hang on to one of her two remaining titles made a reassuring start as she quashed the challenge of one of the tour's brightest young hopes to reach the last 16 of the Dubai Open.

The defending champion's 6-2, 6-3 win over Sabine Lisicki, the 20-year-old Wimbledon quarter-finalist, contained consistent serving, well-timed increases in pressure, and a conspicuously tight focus.

A good week here is important for the five-time Wimbledon champion's belief that, approaching her 30th birthday, she remains capable of winning more majors, and that need showed in the quality of her performance.

There was only one brief moment when it seemed that the hard-hitting but variable German might find sufficient control to get into the match - when she played a brilliant game to break Williams' serve for the only time, and edge up to 3-4 in the second set.

Williams responded immediately, applying extra pressure on her returns to break Lisicki's delivery a fourth time, then smartly closing out the match for the loss of only a point.

She had been put through her paces robustly by her father Richard, before the match, and it appeared to have helped.

"I still try to listen to him," she said, smiling, "and not to rebel against what he says."

The champion's sharp start earned her a meeting with Belarus' Olga Govertsova, a surprise survivor who is coached by her brother, and who brought down the 14th seeded Italian, Francesca Schiavone, in straight sets.

If Williams gets past that as she should, she could go on to a semi-final with the top-seeded Caroline Wozniacki.

However the 19-year-old Dane had to combine resilience and level-headedness to fight back from 1-5 down against an in-form Dominika Cibulkova to win 6-2, 7-6 (7/2).

The buoyant and mobile Slovakian belied her world number 30 ranking to get the better of some athletic baseline exchanges in the middle of the match, and was within two points of taking the second set while serving at 5-2.

"I was getting a bit nervous," admitted Wozniacki.

"But I went out there and I fought and didn't give up, and felt like I was in there all the time."

Wozniacki next plays Shahar Peer, who on Monday became the first Israeli woman to compete in a UAE state, and who scored a high quality win for the second successive day.

Having beaten the 13th seeded Yanina Wickmayer in the first round, Peer now outplayed Virginie Razzano, last year's runner-up, by 6-2, 6-2.

The commitment required of Peer's effort was underlined by her once again overcoming the distractions of careful security, with special arrangements for accommodation, transport, changing and the scheduling of her matches.

"I am very happy with my performance," said the Israeli.

"It was a difficult day for me yesterday because I had two matches and, you know, a lot of emotions, so I am very happy I could be out there, and playing very very good tennis today."

But even though the 22-year-old now faces the favourite in a plum match, Peer will again compete on a well-protected outside court rather than the much more open and conspicuous centre court.

One other seed fell, the fourth-seeded Olympic champion Elena Dementieva and coming here on the back of the Paris Indoor title last Sunday, who retired with a bad shoulder against Daniela Hantuchova; two more seeds, Jelena Jankovic, and Li Na, drifted into trouble and struggled their way out again.

Jankovic, the former world number one, was 1-3 down in the final set against Arazane Rezai, the rising world number 21, before slowing down the French woman's forceful attack just enough to sneak a 4-6, 6-4, 7-5 win.

And Li Na, whose semi-final finish at last month's Australian Open has lifted her to a career-high world number ten, was similarly 1-3 down in the decider, before fathoming an answer to the difficult left-handed angles of Maria Jose Martinez Sanchez, and surviving 7-6 (9/7), 2-6, 6-4.