World number one and top seed Serena Williams launched her bid to win a fourth consecutive US Open and complete a calendar Grand Slam by overwhelming 86th-ranked Russian Vitalia Diatchenko for her 29th consecutive Slam match triumph, while Serbia's Ana Ivanovic was knocked out of the tournament on Monday.
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 is chasing 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.
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. "I felt the support and love on this journey and milestone I'm trying to take one match at a time," Williams said. "I feel so good. I'm so ready. I'm at home, where it all began for me in '99. It all feels great."
Williams advanced to a second-round match against Dutch qualifier Kiki Bertens, who eliminated Croatian Mirjana Lucic-Baroni 3-6, 6-4, 6-2. "If I can just stay relaxed and stay in the points and stay calm and stay happy out there, I have to look at it as I have nothing to lose."
Williams lost plenty of potential obstacles in her march to history on day one as top-10 women's seeds 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 the quarter-finals.
Williams, who owns six US, Australian Open and Wimbledon titles plus three French Open crowns, won her 22nd US Open match in a row since her last loss, to Ausstralia's Samantha Stosur in the 2011 final. Williams has won eight Slam titles since.
Ana Ivanovic after losing a point to Dominika Cibulkova in their women's singles first-round match of the 2015 US Open at the USTA National Tennis Center in New York, on August 31, 2015. (AFP Photo)
Serena's top rivals ousted
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.
The match wasn't much of an upset as Ivanovic had a tough draw against Cibulkova, a former top-10 player and Australian Open runner-up whose ranking had fallen to 50th because of injury. She had undergone surgery on her left Achilles in February and missed more than four months.Cibulkova was the seeded player being upset in the first round of the past two US Opens, including a loss to 15-year-old American CiCi Bellis a year ago.
After the injury-forced withdrawal of Russian third seed Maria Sharapova, Ivanovic had been Williams' top-ranked rival. That status then 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 (5).
One of Serena's rivals who advanced was older sister Venus, a seven-time Grand Slam champion. The 23rd seed outlasted Puerto Rico's Monica Puig 6-4, 6-7 (7), 6-3.
Ivanovic's fellow Serb Jelena Jankovic, seeded 21, also crashed out in the first round, losing to Océane Dodin of France 2-6, 7-5, 6-3. Americans CoCo Vandeweghe, Bethanie Mattek-Sands, and Madison Keys also advanced.
Russia's Ekaterina Makarova and Anastasia Pavlyuchenkova won their respective first-round encounters, but fellow Russian and 2004 US Open winner Svetlana Kuznetsova was eliminated by Kristina Mladenovic of France.
Ukraine's Elina Svitolina advanced, and so did struggling Canadian Eugenie Bouchard.