NEW YORK (AFP) - Top seed Ana Ivanovic struggled but held on to win her opening match, while a pair of wannabe number ones advanced in straights sets during day two of the US Open. World No. 1 Ivanovic, who captured the French Open earlier this year for her first Grand Slam title, didn't make the opening statement she had planned on Tuesday. The 20-year-old Serbian survived a scare by beating Vera Dushevina 6-1, 4-6, 6-4 at the Billie Jean King National Tennis Centre. "Obviously my lack of practice showed a little," Ivanovic said. "This match is going to help me because it was so challenging. "I was missing a lot of match practice so I got a tough one today." Olympic silver medallist Dinara Safina and Serena Williams won their first round matches in straight sets on Tuesday. Both have a chance at supplanting Ivanovic as the top ranked WTA player if they reach the finals in the 20.6 million dollar event. On the men's side of the draw, Roger Federer began his quest for his fifth consecutive US Open title in stunning fashion with a dominating 6-3, 6-0, 6-3 win over Maximo Gonzalez. "It was a good match to start off with," Federer said. "I thought I served well and really moved good for the first round. I went on a good roll."Safina, who is trying to put a fitting exclamation point on a superb season, defeated Kristie Ahn 6-3, 6-4. The 22-year-old Safina, has won three titles in 2008 but hasn't made it past the quarter-finals in the US Open. Two-time champion Serena Williams rolled to an easy win by beating Kateryna Bondarenko 6-1, 6-4.The 26-year-old American continued her solid play on hardcourts by firing six aces en route to a victory in just 56 minutes. Sister Venus also booked a second round spot with a win over Aussie Samantha Stosur.The women's draw is wide open this year as the last three champions (Maria Sharapova, Kim Clijsters, Justine Henin) are all absent.Ivanovic had to overcome some anxious moments in the third set as she double faulted on her first match point before clinching the victory on her second match point.She moves through the second round where she will face Julie Coin of France who beat Australian Casey Dellacqua 7-6 (8/6), 7-6 (7/4).Safina hammered five aces and fired 20 winners to just eight for American qualifier Ahn.It would be a windfall victory for Safina if she breaks through and wins the US Open.She placed first the US Open Series leading up to the final Grand Slam of the season which means she would receive a one million dollar bonus in addition to the 1.5 million dollars in first place prize money.She moves through to the second round where she will face Taiwan's Chan Yung-jan who beat Stephanie Cohen-Aloro of France 4-6, 7-5, 6-3.The second seeded Swiss star Federer lost his world No. 1 ranking last week to Rafael Nadal. He is hoping that another win at Flushing Meadows can salvage a season where he has won just two titles and failed to defend his Australian Open and Wimbledon crowns. Against Gonzalez, he fired 15 aces and hammered 39 winners on the main Arthur Ashe Stadium court in front of an evening crowd of about 20,000. He also converted seven of 13 break point opportunities and won 73 percent of his first serves. "This takes a little bit of pressure off me because I know a little more about where my game is at," Federer said. "I have to play more aggressively on hardcourt." Federer dispatched Argentina's Gonzalez in a scant 82 minutes and advances to the second round where he will face Thiago Alves of Brazil. Other seeded mens winner included, Fernando Gonzalez, Fernando Verdasco, Tommy Robredo, Ivo Karlovic and Igor Andreev all won their opening matches. Former world number one Marat Safin beat American journeyman Vince Spadea 3-6, 6-2, 6-3, 4-6, 6-4 while Germany's Tommy Haas posted a mild upset over French 12th seed Richard Gasquet 6-7 (3/7), 6-4, 5-7, 7-5, 6-2.