- Roger Federer wins opener at U.S. Open
- Five-time champion beats Slovenian Grega Zemlja
- Federer lowly seventh seed after indifferent 2013
- Caroline Wozniacki and Petra Kvitova come through testing matches
Five-time champion Roger Federer breezed through a potentially testing first round match at the U.S. Open Tuesday to lift some of the pessimism surrounding his latest title bid.
The grand slam singles record holder, seeded as low as seventh after an indifferent 2013, had too much know how for Slovenian Grega Zemlja in winning 6-3 6-2 7-5.
A shock second round exit at Wimbledon and injury concerns left many doubting 32-year-old Federer would be a major factor as he bids for this 18th slam.
But in a match carried over from Monday due to bad weather, the Swiss maestro was always on top.
His only hiccup came when he surrendered a break in the third set before eventually closing out the match on the Arthur Ashe Stadium Court.
He will play Argentina's Carlos Berlocq in the second round, with a possible quarterfinals against No.2 seed Rafael Nadal on the horizon.
"I felt great," Federer said. "Day sesion or night session it doesn't really matter when you play on Arthur Ashe Court," he told fans.
Top seed and world No. 1 Novak Djokovic made short work of his first round opponent, defeating Lithuanian Ricardas Berankis 6-1 6-2 6-2 in 81 minutes.
The 2011 champion hit 28 winners in the match and dropped his serve in the third set, but recovered to break back in the next game to serve out a routine victory.
Djokovic only needs to reach the semi-finals to retain his top ranking. He faces Germany's Benjamin Becker in the second round.
Wimbledon semifinalist and 14th seed Jerzy Janowicz was knocked out in the first round at Flushing Meadows for the second year in a row, losing in straight sets to Argentina's Maximo Gonzalez.
In the women's draw 2011 champion Samantha Stosur was stunned by 17-year-old Victoria Duval, surrendering a one-set lead to lose 5-7 6-4 6-4 to the 296th-ranked American.
Duval, who lost in the first round of last year's event to Kim Clijsters, was delighted with her own performance.
"I think I played amazing today -- it was incredible, the whole match was just really an incredible match and I'm happy I pulled it through," the Miami-born starlet told the WTA's official website.
"Obviously it's a great feeling to beat a past champion. And Sam is amazing. Although she didn't play nearly her best today, I played amazing, so I'll take it!"
Former Wimbledon champion Petra Kvitova and former World No.1 Caroline Wozniacki both withstood testing challenges from Asian players in their first round matches.
Seventh seed Czech Kvitova, the 2011 winner at Wimbledon, dropped the middle set against Japan's Misaki Doi before going through 6-2 3-6 6-1.
Wozniacki, being supported at Flushing Meadows by golfing boyfriend Rory McIlroy, had a slightly easier task against Chinese qualifier Duan Ying-Ying.
But having won the first set 6-2, the Danish sixth seed trailed by a break in the second before recovering to close out it out 7-5.
Another former No.1, Serbia's Ana Ivanovic, also showed good early form with a straight sets win over Georgian Anna Tatishvili 6-2 6-0.
Victoria Azarenka powered through her opening match in little more than one hour, handing her German opponent Dinah Pfizenmaier a double donut -- winning 6-0 6-0. The No. 2 seed will face Aleksandra Wozniak in the next round.