Serbia's Janko Tipsarevic made a winning return to the ATP Tour following an injury to his left foot that almost ended his career.
The 30-year-old has been sidelined for 17 months after two operations to remove a benign tumour, which have stripped away "80% of his sole".
But he saved two match points to beat Guilherme Clezar in the US Clay Court Championship first round in Houston.
"I felt like this was a match I needed to win," Tipsarevic said.
"I was ready, and I was fit. I had no confidence coming in, but saving match points with forehand winners down the line maybe proved otherwise. I really felt I had to win this match, and I would have been really sad otherwise."
Former world number eight Tipsarevic beat Brazilian qualifier Clezar 6-4 3-6 7-6 (9-7) in two hours and 38 minutes.
"I'm in pain everywhere, but the foot is good," he added. "I can tell you that we take [the muscles in our feet] completely for granted."
Tipsarevic, who returned to action by playing a doubles match with fellow Serb Novak Djokovic in Miami last week, knows that a third surgery on his injured foot will lead to retirement.
"My life would not be in danger," he said. "But I could not play tennis again. Basically [the second surgery] took away about 80 percent of my sole. That's why it took so long [to return]."