NEW YORK (AP) – Juan Martin del Potro is the lowest-ranked man to reach the U.S. Open quarterfinals since Jimmy Connors in 1991, and it turns out a 27-year-old Argentine can share much in common with a 39-year-old American.
At its root, the story captivating fans at Flushing Meadows is the same: the former champion making an unlikely run to reclaim past glory.
In del Potro's case, his body has betrayed him through injuries, not age — multiple left wrist surgeries that kept him from the majors for 2½ years. The only thing missing from his tale so far at this tournament is a marathon match.
Monday's victory was particularly brief after eighth-seeded Dominic Thiem retired in the second set because of a bum knee. For once, an injury was aiding del Potro, not hindering him.
Still tired after the stunning run to an Olympic silver medal that announced him as a contender again, he got a huge break in spending only 72 minutes on court. Del Potro has played just 10-plus sets through four rounds and got in some extra hitting after Monday's match abruptly ended.
Thiem took a medical timeout to have trainers look at his right knee after the second set's fifth game. He returned to the court for one point before deciding he couldn't go on.
Del Potro had won the first set 6-3 and was up a break in the second. He had trainers massage his right shoulder on a few occasions but looked fine after coming back from down an early break.
Thiem said his knee started hurting three days earlier, and he speculated it was the indirect result of blisters on his feet — he needed to alter his gait to compensate. Late in the first set Monday, it started getting worse. He didn't want to take any risks with a knee injury and planned to get an MRI.
"I couldn't bend it too much the last three days," he said. "So I was all the time a little bit handicapped."
Thiem, who turned 23 on Saturday, has had a breakthrough year, reaching the French Open semifinals and cracking the top 10. But all those victories came with a cost — a tour-high 69 matches, and the long season had started to wear on his body. On top of that, he had played 12 sets through three rounds at the U.S. Open.
"I never expected to play that many matches, of course, this year," he said. "For sure next year I'm going to change it up a little bit."
Del Potro's quarterfinal opponent could be third-seeded Stan Wawrinka, who has already made a cameo in this saga. In del Potro's first Grand Slam back, his second-round upset of Wawrinka at Wimbledon initially hinted at a return to the top of the sport.
"He will be the favorite to win in that match," del Potro insisted, before adding: "But anything can happen in this event for me. I got the power from the crowd in every match."
On the 25th anniversary of the 174th-ranked Connors' rousing run to the semis, del Potro, at No. 142 in the world, is a win away from that stage. He's already in his first major quarterfinal since 2013 Wimbledon.
Del Potro recalled in his on-court interview after Monday's match how sad he was to watch the U.S. Open on TV, stuck at home the last two years.
"I didn't expect to be in quarters in my second Grand Slam after my comeback," he said later. "I'm playing good tennis. My level is growing up every day."
Somebody noted that at the 2009 U.S. Open, which ended with a victory over Roger Federer in the final, he beat an Argentine, an Austrian and a Spaniard along the way — just as he's done this year.
Del Potro burst into laughter and replied: "I only remember the finals against Roger, and he's not here. But it's a good point."