Ana Ivanovic needed every scrap of her youthful ebullience on Tuesday to narrowly avoid the humiliation of becoming the first top-seeded woman to lose in the opening round of the US Open.

- Images from Day 2

It took the 20-year-old Serbian just over two hours to make her standing as world number one count against a valiant Vera Dushevina and she booked her place in round two with a 6-1, 4-6, 6-4 triumph.

Roger Federer [Images] may no longer occupy the top spot in the men's rankings after being dethroned by Rafael Nadal [Images] last week but he showed he was still the man to beat after handing obscure Argentine Maximo Gonzalez a 6-3, 6-0, 6-3 masterclass.

From 3-3 in the first set, the four-times champion hit cruise control to win 10 successive games and it took him only 82 minutes to complete victory.

"It's been a hard year... (but) the Olympic doubles gold really gave me a great lift and I'm really inspired to do well here," said Federer, who rescued a less than stellar season by striking gold in Beijing [Images] with Stanislas Wawrinka.

Ivanovic also needed some inspiration to stay alive on Tuesday.

Playing as if she had taken a leaf out of Brad Gilbert's tennis manual 'Winning Ugly' or perhaps still troubled by a right thumb injury which ruled her out of the Olympics [Images], Ivanovic randomly misfired her shots to notch up 40 unforced errors.

It led to a fan screaming out in desperation: "You're number one for a reason." She heeded the call to subdue the 57th-ranked Russian on her third match point.

"It was ugly, to put it mildly," summed up John McEnroe, who was commentating on the match for an American network.

Realising how close she had come to establishing an unwanted record, Ivanovic said: "I really hope I can stick around for some time."

HOT STREAK

Her potential quarter-final opponent, sixth seed Dinara Safina, kept up her recent hot streak to beat grand slam debutante Kristie Ahn 6-3, 6-4.

Slovakian 11th seed Daniela Hantuchova [Images], however, fell by the wayside when she was flattened 6-4 6-2 by qualifier Anna-Lena Groenefeld. Tommy Haas completed a good day for the Germans when he ousted men's 12th seed Richard Gasquet 6-7, 6-4, 5-7, 7-5, 6-2.

Safina made no allowances for Ahn, who at 16 is the youngest woman in the draw, and showed off her repertoire of groundstrokes and thundering serves to get her campaign off to a flying start.

The Russian is one of five players who could topple Ivanovic from the top spot by the end of the tournament should the Serbian trip up early.

French Open runner-up Safina, who has a 16-1 win-loss record since Wimbledon [Images], was joined by her hot-headed brother Marat Safin [Images] in the last 64.

Safin raged and ranted at umpire Carlos Bernades after he was controversially foot-faulted on a second serve late in the fourth set against Vince Spadea.

With Bernades refusing to overturn the call -- which gave Spadea set point -- Safin turned the air blue, incurred a warning and slumped into his chair refusing to play on.

The incident effectively cost the former world number one the set but he eventually put a lid on his emotions to carve out a 3-6, 6-2, 6-3, 4-6, 6-4 win.

"It's stupid rules that somebody made in 1850 and now they give me the problems with these things and it shouldn't be that way," fumed Safin, the 2000 champion.

"How can a guy see... a foot fault... with sunglasses from 35 feet metres away? It doesn't make any sense."

Fourth seed Serena Williams [Images] relied on her 20/20 vision as she began her title charge with a 6-1, 6-4 thumping of Kateryna Bondarenko and her sister Venus protected the family reputation with a 6-2, 6-3 win over Samantha Stosur.

Former Australian Open and Wimbledon champion Amelie Mauresmo flirted with danger before she defeated fellow Frenchwoman Nathalie Dechy 4-6, 6-3, 6-2.

• Complete tennis coverage
• All you want to know about Sania Mirza