NEW YORK -- For years and years, a first-round victory by Venus Williams at a major tournament would hardly merit a mention.

She is, after all, a seven-time Grand Slam singles champion. She's been the runner-up another seven times.

She was ranked No. 1, owns Olympic gold medals, and is second to her younger sister Serena among active women in several key categories, including Grand Slam match wins, with 215.

And yet nowadays, at age 33, two years removed from being diagnosed with an autoimmune disease that saps energy, hampered much of this season by a bad lower back, and her ranking down to 60th, Williams entered Day 1 at the 2013 U.S. Open having won a total of three matches over the past five Grand Slam tournaments. Plus, she was facing 12th-seeded Kirsten Flipkens, who was a semifinalist at Wimbledon last month and beat Williams on a hard court this month.

Looking very much like the player she used to be, Williams smacked serves at up to 120 mph, returned superbly, covered the court well enough to hit a handful of swinging volley winners, and beat Flipkens 6-1, 6-2 Monday to reach the second round at Flushing Meadows.

"I stay positive because I know I can play great tennis. Sometimes you just have to go through more than what you want to go through," the American said.

Serena Williams began her title defense with a 6-0, 6-1 victory, a performance so thoroughly impressive that her opponent, 2010 French Open champion Francesca Schiavone, was prompted in a brief moment of levity to seek comfort by hugging a ball boy.

  • Wiping away tears, former top-five player James Blake announced that he will retire from tennis after the U.S. Open.