The three-time defending champion won 6-0, 2-0 after only 30 minutes at Arthur Ashe Stadium when Diatchenko retired with a left foot injury, advancing Williams into the second round at Flushing Meadows. The 33-year-old American chases the first calendar Grand Slam since Steffi Graf in 1988 and a 22nd career major title to match Graf's Open Era record, two shy of Australian Margaret Court's all-time mark.

Top-ranked Novak Djokovic cruised into the men's second round but Japanese fourth seed Kei Nishikori crashed out after his runner-up effort last year. Williams praised the New York crowd, which has adored her since she captured her first major title at the 1999 US Open as a teen prodigy.

Williams advanced to a second-round match against Dutch qualifier Kiki Bertens, who eliminated Croatian Mirjana Lucic-Baroni 3-6, 6-4, 6-2. Williams lost plenty of potential obstacles in her march to history on day one as top-10 women's seeds Ana Ivanovic, Karolina Pliskova and Carla Suarez Navarro exited with opening-match losses.

That left 12th seed Belinda Bencic -- who ousted Bulgarian Sesil Karatancheva 6-1, 6-2 -- as the top-rated foe in Williams' half of the draw. Williams, who lost to Bencic in the Toronto semi-finals, could see the Swiss teen again in a quarter-final.

Williams, who owns six US and Australian Open and Wimbledon titles plus three French Open crowns, won her 22nd US Open match in a row since her last loss, to Aussie Samantha Stosur in the 2011 final. Williams has won eight Slam titles since then.

Djokovic needed only one hour and 11 minutes to capture a 6-1, 6-1, 6-1 victory over Brazil's Joao Souza.

Djokovic's highest-ranked possible semi-final foe had been Nishikori, but last year's runner-up exited the US Open at the first match for the third time in five years as France's 41st-ranked Benoit Paire saved two match points and defeated the Japanese star 6-4, 3-6, 4-6, 7-6 (8/6), 6-4.

Paire, who had never before beaten a top-five foe, fired 21 aces to only three for Nishikori and blasted 64 winners, 30 more than Nishikori, with 67 unforced errors, 31 more than the Asian number one. Nishikori led the tie-breaker 6-4 but swatted a forehand long, watched Paire smack two service winners and then Nishikori netted a forehand to force a fifth set.

Paire, who won his first ATP title last month at Bastad, broke for a 3-2 lead and held to the finish to win after three hours and 14 minutes. Defending champion Marin Cilic of Croatia won his opener 6-3, 7-6 (7/3), 7-6 (7/3) over Argentine qualifier Guido Pella.

Slovakia's 50th-ranked Dominika Cibulkova ousted seventh-seeded Ivanovic 6-3, 3-6, 6-3, delivering the Serb star's earliest US Open exit since 2009. After the injury-forced withdrawal of Russian third seed Maria Sharapova, Ivanovic had been Williams' top-ranked rival.

That status fell to Czech eighth seed Pliskova, who promptly lost to American Anna Tatishvili 6-2, 6-1, and then to 10th seed Suarez Navarro, who fell to Czech Denisa Allertova 6-1, 7-6 (7/5). One Williams rival who advanced was her older sister Venus, a seven-time Grand Slam champion. The US 23rd seed outlasted Puerto Rico's Monica Puig 6-4, 6-7 (7/9), 6-3.

Latest News from Sports News Desk