Facing two break points at 1-3 in the second set, it seemed as if Henin’s dramatic win over Olympic gold medalist and fifth-ranked Elena Dementieva on Wednesday had sapped too much energy. It was only the seventh match for the seven-time Grand Slam winner since she returned from 20 months off the tour.

But Henin managed to hold that game, hitting the lines with her groundstrokes, and in the next game converted her first break-point chance. As soon as Henin found her range, the match was as good as over.

“I kind of survived a little bit today,’’ Henin said. “It’s always good to win this kind of match because I came back from nowhere.

Former No. 1-ranked Andy Roddick was challenged all the way in a 6-7 (7-4), 6-4, 6-4, 7-6 (7-3) win over Feliciano Lopez. He will play 2007 runner-up Fernando Gonzalez of Chile, who was backed by a noisy Chilean contingent in stifling conditions on Showcourt 2 as he beat Kazakhstan’s Evgeny Korolev, 6-7 (7-5), 6-3, 1-6, 6-3, 6-4.

Roddick broke Lopez in the third game of the second set and the ninth of the third set, serving out at love both times.

Henin, unranked and playing on a wild-card entry, had a momentary lapse in the deciding set when Kleybanova broke her serve, but otherwise dominated the last 10 games.

Only two nights earlier, Henin had to save set points to finish off Dementieva in a tiebreaker, drawing on the experience of losing in similar circumstances to Kim Clijsters after holding match points in the Brisbane International final Jan. 9.

That was Henin’s first tournament since she quit while holding the No. 1 ranking in May 2008. In what is shaping as the Belgian quarter, Henin must beat Yanina Wickmayer to have a chance at a quarterfinal against Clijsters.

Wickmayer, who is ranked No. 16 but unseeded because she was under a suspension - since overturned - for breaching the World Anti-Doping Agency’s “whereabouts rule’’ when direct entries closed for the Australian Open - advanced, 6-1, 6-7 (7-4), 6-3 over Sara Errani.

Second-seeded Dinara Safina had an easier third-round match, advancing with a 6-1, 6-2 victory over Britain’s Elena Baltacha in her first match on Rod Laver Arena since her lopsided loss to Serena Williams in last year’s final.

Safina will have a more difficult assignment next round against fellow Russian Maria Kirilenko, who beat Italian Roberta Vinci, 7-5, 7-6 (7-4). Kirilenko had an upset win over 2008 champion Maria Sharapova in the opening round.

Former No. 1-ranked Jelena Jankovic was upset, 6-2, 6-3, by No. 31 Alona Bondarenko.

Roger Federer, the king of tennis, met Britain’s Prince William after dispatching Victor Hanescu, 6-2, 6-3, 6-2, in 99 minutes yesterday.

“Your Royal Highness, welcome to the world of tennis,’’ Federer said. “Thanks for coming.’’

Prince William also met women’s champion Serena Williams, who defeated Czech Petra Kvitova, 6-2, 6-1, to set up a third-round match against Spain’s Carla Suarez Navarro. Navarro ousted Venus Williams in the second round last year.

Venus has already improved on that, defeating Sybille Bammer, 6-2, 7-5.