Anja Niedringhaus, Associated Press
Serbia's Novak Djokovic reacts during his second round match against Russia's Marat Safin on the Centre Court at Wimbledon, today.

WIMBLEDON, England — Novak Djokovic was upset in straight sets by Marat Safin in the second round Wednesday, ending the Serb's chances of testing his theory about Roger Federer's vulnerability at Wimbledon.

The 75th-ranked Safin won 6-4, 7-6 (3), 6-2 on Centre Court. It was a stunning loss for the third-ranked Djokovic, who came to the All England Club confident after beating top-ranked Federer in the semifinals at this year's Australian Open en route to his first Grand Slam tournament title.

Top-ranked Federer only had a minor hiccup — dropping serve once, the first time since Roland Garros — before getting past Robin Soderling 6-3, 6-4, 7-6 (3) to extend his streak on grass to 61 matches. The Swiss star looked anything but vulnerable as he continued his bid for a sixth straight Wimbledon title.

Women's No. 1 Ana Ivanovic, another Serb, struggled but won. The French Open champion saved two match points — including one that bounced off the net chord for a winner — in the second set before overcoming 29-year-old Frenchwoman Nathalie Dechy 6-7 (2), 7-6 (3), 10-8.

Two-time champion Serena Williams had less trouble, advancing 6-4, 6-4 over Urszula Radwanska on Court 2, called the "graveyard of champions" for its history of upsets.

Djokovic came up against one of the toughest second-round opponents he could have drawn.

Former No. 1 Safin has won two Grand Slam titles. One came when he upset Federer in an Australian Open semifinal en route to the 2005 title. Safin beat Djokovic in the first round of that tournament — their only previous meeting.

"It was certainly a very bad day for me," the 21-year-old Djokovic said. "I didn't do anything that I was supposed to — he was very solid in all segments."

Djokovic had said Federer was vulnerable after his recent lopsided French Open loss to No. 2-ranked Rafael Nadal.

The hype surrounding those comments set up the possibility of an enticing semifinal here. Now, it will be Safin who will try to go down that path.

But not before offering some thoughts on what led to his victory over Djokovic.

"He didn't impress me with his game today. I could read his serve. I could return," the 28-year-old Russian said. "I could stay with him from the baseline, and that's it."

Safin said he came in under the radar, and that Djokovic had all the pressure.

"He's the one who has to win matches. For me, nobody expects anything," said Safin, admitting that he had not dared look beyond the second round. "Now, I'll have to check — the way I'm playing now, I could go far."

Djokovic was far from convincing, playing on a surface he is not entirely comfortable on and struggling with his serve in a blustery breeze. After saving three match points, he served a double-fault to give his Russian opponent a fourth, then double-faulted for the 10th time to concede.

"I was serving a lot of double-faults, which is unusual," said Djokovic, who was broken twice in each of the first and third sets and only broke Safin's serve once. "I was just not finding my momentum."

Ivanovic was erratic against 97th-ranked Dechy, who saved two match points on her own serve in the 12th game of the third set.

Ivanovic set up three more match points at 0-40 six games later and, after Dechy saved one, the 20-year-old Serb squealed with delight and kissed the net after hitting a forehand winner to end it in 3 hours, 24 minutes.

"It was an amazing match ... one of my longest ever," said Ivanovic, who dropped her service five times but had twice as many winners (72) as unforced errors (36). "In the second set I saved some match points and from that point on I just thought it's my second chance."

Ivanovic next plays China's Zheng Jie, a 6-2, 7-5 winner over Britain's Elena Baltacha.

In other women's matches, 2006 champion Amelie Mauresmo recovered to win 4-6, 6-1, 6-1 over Virginia Ruano Pascual and 2007 finalist Marion Bartoli beat Tatiana Perebiynis 6-2, 7-5.

Also advancing were No. 4 Svetlana Kuznetsova, No. 8 Anna Chakvetadze, and No. 18 Nicole Vaidisova, a quarterfinalist last season.

Lleyton Hewitt, the only other Wimbledon champion in the men's draw, survived Court 2 with a 7-6 (4), 6-0, 6-2 win over Albert Montanes of Spain.

Others advancing were No. 10 Marcos Baghdatis, No. 13 Stanislas Wawrinka and American Bobby Reynolds, who had a 4-6, 7-6 (10), 6-4, 6-4 victory over Canadian Frank Dancevic.

Another former No. 1, Juan Carlos Ferrero had to retire with a leg injury in the third set when he trailing Mischa Zverev.

Safin is a dangerous opponent now, even though grass isn't his favorite surface and Wimbledon is the only major where he hasn't advanced beyond the quarterfinals.

He next plays 29th-seeded Andreas Seppi, who beat Florent Serra 6-3, 6-7 (4), 6-2, 6-7 (5), 6-4.

"I had opportunities, but I just made some unforced errors, which were really uncharacteristic," said Djokovic, who shook his head while walking to the net to hug Safin. "Safin has his ups and downs, and is known for his mental instability in some ways, but he's still a great player."

Djokovic reached the semifinals last year but had to retire against Nadal with blisters. He was hoping to meet Nadal in the final this time.

"A lot of expectations from my side and all the people that are following my career," he said. "I just have to take the best things out of it and use it for the future — certainly I expected to go far."