At 33, slowed the past couple of years by an autoimmune disease that saps energy, and hampered much of this season by a bad back, Williams knows by now that such queries are going to arrive, particularly after results such as her 6-3, 2-6, 7-6 (5) loss to 56th-ranked Zheng Jie of China on a wet Wednesday at Flushing Meadows. It is the third year in a row that the two-time champion is out of the U.S. Open after two rounds.
"If I didn't think I had anything in the tank, I wouldn't be here," said Williams, who was ranked No. 1 in 2002 and is currently 60th. "I feel like I do, and that's why I'm here."
The American acquitted herself well for stretches, erasing deficits over and over again, until she simply ran out of solutions against Zheng, a former top-15 player and twice a major semifinalist.
"I just kept trying to fight today," Williams said.
In what she took as an encouraging sign, Williams was out there for 3 hours, 2 minutes, tying for the fifth-longest women's match since 1970 at the U.S. Open. The third set alone lasted 1½ hours.
"I was like, 'Wow, this is a marathon,'" Williams said.
Near the finish line, she faltered. On the final two points, Williams missed a volley, then a return. She wound up with 44 unforced errors in all, half on forehands, in part because Zheng kept scrambling along the baseline to get to balls and block them back, making Williams hit extra shots.
During her on-court interview, Zheng addressed the partisan crowd that was raucously pulling for Williams in Louis Armstrong Stadium, saying: "First, I want to say, 'Sorry, guys.'"
Rain began falling in the early afternoon, jumbling the schedule, and eight women's singles matches were postponed entirely, including Williams' younger sister Serena against Galina Voskoboeva. More than four hours of delays during the day meant 2012 champion Andy Murray did not play his first point of the tournament until 9:55 p.m., making for the third-latest start to a U.S. Open night session.
Men were playing in the first round, women in the second, and Murray's 6-2, 6-4, 6-3 victory over 49th-ranked Michael Llodra of France began in Arthur Ashe Stadium only after 2009 champion Juan Martin del Potro wrapped up a contentious 6-3, 6-7 (5), 6-4, 7-6 (7) victory over 74th-ranked Guillermo Garcia-Lopez of Spain that stretched more than four hours.
Murray, who last month became the first British man in 77 years to win Wimbledon, needed only a little more than 1½ hours to get past Llodra, making only five unforced errors while compiling 34 winners.
"I'm very happy everyone stayed behind to watch," Murray told the spectators afterward. "I know it was late, but it made it special to come back to a full house."
Del Potro was irked by his opponent's repeated calls for a trainer to treat his left leg, while Garcia-Lopez kicked a towel and got into an argument with the chair umpire over a ruling to replay a point in the closing tiebreaker.
No. 17 Kevin Anderson of South Africa, No. 20 Andreas Seppi of Italy, No. 21 Mikhail Youzhny of Russia, 2001 U.S. Open title winner Lleyton Hewitt and 109th-ranked American wild-card entry Tim Smyczek also were among the winners. But No. 16 Fabio Fognini, No. 24 Benoit Paire and No. 29 Jurgen Melzer lost, meaning 10 of the 32 seeded men bowed out in the first round.
Women's winners included 2011 French Open champion Li Na, 2012 Wimbledon runner-up Agnieszka Radwanska and 30th-seeded Laura Robson of Britain. Robson beat Li last year in New York, and now they'll have a rematch.
"I remember being so nervous when I walked on court," the 19-year-old Robson said. "She made a lot of mistakes in the first set, which helped quite a lot. Hopefully she'll do that again."
Venus Williams and Zheng played all of two points before being interrupted by showers. When they resumed two hours later, Williams kept making mistakes.
"I couldn't pray a ball in," she said.
But in the second set, Williams more like someone who won the U.S. Open in 2000 and 2001, and five Wimbledon titles.
Every point she won, it seemed, drew clapping and screaming from on-their-feet spectators.
"I love that. I wish I could play some more for that," Williams said. "I want to come back here just for that, at this point."
A drizzle halted action elsewhere, but Williams and Zheng continued.
Zheng led 4-1 in the tiebreaker, before Williams made one last stand. But at 5-all, Williams put a backhand volley into the net as she lost her footing.
"I should have made the shot," Williams said. "I was just rushing."
That gave Zheng her first match point, and Williams' backhand return missed, ending her stay in the singles draw.
As she pointed out more than once during her news conference, there's still doubles to play with her sister.
The older Williams hasn't been ranked in the top 10 in 2½ years. The last time she made it beyond the third round at a major tournament was a fourth-round appearance at Wimbledon in 2011.
At the 2011 U.S. Open, Williams withdrew before her second-round match, announcing she had Sjogren's syndrome, an illness that causes joint pain and fatigue.
She lost a three-setter in the second round in New York last year.
Two of her previous four trips to major tournaments ended in the first round, including at the French Open in May. Because of her back, Williams sat out Wimbledon for the only time in her career in June.
But she is not ready to say goodbye.
"I've had a tough set of circumstances to work through, too, especially this year, last year, and the year before. I've been dealt some cards that aren't as easy to deal with, but I have to play with them. The last few months haven't been easy, coming back from the back injury," Williams said.
"I feel like it's definitely affected my game, but I'm working on it," she added. "I'm a fighter."
O Venus Williams is beaten by 56th-ranked Zheng Jie 6-3, 2-6, 7-6 (5), falling in the second round.
• Defending men's champion Andy Murray earns a 6-2, 6-4, 6-3 victory over 49th-ranked Michael Llodra.
O Second round: Thursday, 11 a.m. and 5 p.m., ESPN2