"I know how I can play, and, you know, there were times when I just physically couldn't do it," the 67th-ranked Mattek-Sands said, "and I think that's really frustrating."
There was hip surgery less than a week after her wedding in late 2008, a torn shoulder in 2011, a broken right big toe in 2012.
Her ranking plummeted from a best of 30th to outside the top 200. She found herself playing in the sport's minor leagues and going through qualifying just to get into tournaments.
"She can take more enjoyment out of it, out of playing," said her coach, Adam Altschuler. "We've got to go do it the day after this and the day after that. But it's great for her to show the world she's this good."
Only 18 of 32 scheduled singles matches were completed, with two-time Australian Open champion Victoria Azarenka and 2011 U.S. Open champion Sam Stosur among the winners. Six were suspended in progress defending champion Maria Sharapova led Canada's Eugenie Bouchard by a set and a break when they stopped and eight were postponed entirely, including Rafael Nadal against Slovakia's Martin Klizan.
Last year's runner-up to Nadal, Novak Djokovic, gestured at the dark, threatening sky between points, as if to admonish the clouds for even considering halting play before he could finish a 6-2, 6-0, 6-2 victory over 83rd-ranked Guido Pella of Argentina.
O Bethanie Mattek-Sands, 28, becomes the fourth U.S. woman to reach the third round. In her 27th Grand Slam tournament, Mattek-Sands beats sixth-seeded Li Na 5-7, 6-3, 6-2.
• Top-ranked Novak Djokovic wins in straight sets and plays Bulgaria's Grigor Dimitrov who has beaten Djokovic this season in the third round.