Hingis was only 16 when she won the Wimbledon title

The Swiss star, who was leading 6-2 before rain stopped play on Monday, took the second set 6-2 in 28 minutes.

The 25-year-old, who won Wimbledon at just 16 in 1997, launched a playing comeback in January after retiring in 2002 because of an ankle injury.

Hingis, seeded 12 this year, will now face Italy's Tathiana Garbin.

Highlights: Wimbledon day two

The former world number one, who lost in the first round on her last appearance in 2001, was delighted to have made a winning comeback.

"It's been a while and it was nice to be back," she said. "I felt comfortable right away. I practised well beforehand - mainly indoors and that's my secret to coming here.

I was a bit tired from my last two matches in Eastbourne but the rain on Monday helped me Justine Henin-Hardenne

"Playing indoors is quicker and the bounce is right. You can't really teach people how to play on grass, only tell them to move in and have an offensive game."

Justine Henin-Hardenne began her quest for a first Wimbledon title with an emphatic 6-0 6-1 victory over 19-year-old Meng Yuan of China on Centre Court.

The Belgian, who won the French Open last month and the Eastbourne title last week, suffered the ignominy of losing in the first round last year.

But there would be no repeat of that this year as the 24-year-old broke her opponent in the first game and never looked back.

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"I was a bit tired from my last two matches in Eastbourne but the rain on Monday helped me a little bit," she said.

"I played well, very consistent, pretty aggressive. That's the kind of match you need in the first round."

Second seed Kim Clijsters overcame Russia's Vera Zvonareva 7-5 6-3 in a rain-interrupted match.

The Belgian, leading 5-4 before the rain ended play on Monday, was broken in the first game on Tuesday but broke back immediately and then held serve to take the set.

The 21-year-old Russian, who won in Birmingham earlier this month, continued to fight in the second set but Clijsters had enough power and know-how to secure victory on her fourth match point.

She will now face Ukraine's Viktoria Kutuzova for a place in the third round.

Clijsters was given a useful test

Afterwards Clijsters backed Zvonareva to reclaim her place at the top of the world rankings.

Injuries have caused Zvonareva to slip down the rankings from ninth in 2004 to her current position of 44.

Clijsters said: "I knew I had to play a good match and be ready for her but she surprised me a lot with the way she was moving.

"She'll soon be back to where she was because she's a good player."

Russia's Svetlana Kuznetsova celebrated her 21st birthday with a 6-3 6-2 win over Italian qualifier Romina Oprandi.

The French Open runner-up rattled down five aces to take the first set.

The fifth seed saved break points on her own serve early in the second set before breaking Oprandi to lead 3-2 and completing a comfortable 57-minute win.

She will now play Czech Kveta Peschke, who beat Kristina Brandi of Puerto Rico 6-3 6-0 in the second round.

Pin-up Daniela Hantuchova, the 15th seed from Slovakia, beat Italy's Maria Elena Camerin 6-4 4-6 6-1.

The 27th seed Li Na, the first Chinese player to be seeded in a Grand Slam singles event, made an impressive Wimbledon debut when she thrashed France's Virginie Razzano 6-2 6-0.

But 17th seed Maria Kirilenko of Russia went out 6-2 7-6 (7-1) to Shinobu Asagoe of Japan and 28th seed Sofia Arvidsson of Sweden crashed to a 6-2 6-4 defeat to Eva Birnerova of the Czech Republic.