HOUSTON (AP) Argentina's Juan Monaco took advantage of defending champion Jack Sock's aching shoulder and leg cramps to rally for a 3-6, 6-3, 7-5 victory Sunday, winning his second U.S. Men's Clay Court Championship nine months after major wrist surgery.

''It's amazing, amazing to hold the trophy again in only my fourth tournament back, after three years (without a title),'' Monaco said. ''It's almost like a dream come true for it to happen so fast. The hard work really paid off.''

The 32-year-old Monaco, also the 2012 winner at River Oaks, held off a surging Sock in the third set after taking a 4-1 lead. Sock won the next four games, but suffered the decisive break in the 11th game when, with his left thigh apparently cramping under the cloudy, humid conditions, missed an underhanded serve. Early in the match, Monaco also received attention from the trainer for an apparent back issue.

Sock, the 23-year-old American seeded fourth in defense of his lone ATP World Tour title, said after the match that he'd begun feeling poorly with flu-like symptoms Saturday night. He had won 17 consecutive sets in the event dating to his first-round match last year.

''I felt great all week. I'm not exactly sure what happened with my body,'' Sock said. ''Last night, I didn't feel great. I was sweating in a very air-conditioned room, so maybe (I'm) possibly coming down with something. But that doesn't take away from (Monaco's) battle and fight today. It came down to the wire. I tried my best and put it all out there.''

Monaco won his ninth tour title and first since 2013. Eight of them have come on clay. In August of last year, he left the tour to have an operation in which a damaged tendon in his right wrist was replaced. Earlier this year, he pulled out of the Australian Open because he didn't think he was ready to return.

Monaco said his felt a sharp pain in his back after being broken twice to start the match and that's why he asked for a trainer. He dominated play for a long patch thereafter before Sock made his late charge.

''I was calm because I saw him not in good shape,'' Monaco said. ''But after he called the trainer he played more relaxed with nothing to lose, with no thinking. He was good, but I made mistakes and I was a little bit nervous because of the situation, which is normal. But then I try to just put the ball in, run and don't think too much, just try to win the last ball.''

Monaco insisted he didn't think Sock was trying to use gamesmanship, saying, ''He's a friend, a great guy.''