Tennis is a sport that mostly follows form. Seeded players win more than unseeded players. Those with higher rankings generally rule over their lesser peers. Even in the case of Juan Martin del Potro, ranked 142nd in the world, yesterday’s 6-4, 6-4, 7-6 (3) first-round U.S. Open victory over fellow Argentine Diego Schwartzman, ranked 69th, hardly qualified as an upset.

That’s because del Potro, the 2009 Open champ and 2013 Wimbledon semifinalist, cannot be fairly judged by his rank, which was severely affected by his long absence from the pro tour. A series of wrist operations forced del Potro to miss nine consecutive Grand Slam events before returning at Wimbledon in June.

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Open officials granted him a wild card, based on his past record because, when he has played the majors, he has racked up a 66-27 match won-lost record. His silver medal at the Rio Olympics — losing the final to Andy Murray after beating Novak Djokovic — demonstrated that the 27-year-old del Potro at last is resembling his early-career punch.

“I was really close to quit tennis,” he said after Tuesday’s victory, “because after the first surgery, the second one, and in the end the third one, it was really, really sad moments for me. Nobody knew what I should have to fix my problem. My family and friends help me a lot to never give up. And I think I’m doing well now.

“The worst part of my life is totally in the past, and I’m living a good present and looking forward for a good future. Now I’m playing tennis again and I would like to do this for a few years.”

Other predictable results Tuesday included No. 3 seed Stan Wawrinka’s straight-sets victory over Fernando Verdasco, ranked 46th, which was so routine that Wawrinka was asked about his fuchsia tennis outfit and how he felt about the absence of injured countryman Roger Federer; No. 6 seed Kei Nishikori’s four-set win over 96th-ranked Benjamin Becker; No. 11 David Ferrer’s advance when 57th-ranked Alexandr Dolgopolov retired in the 12th game of the first set and No. 14 Nick Kyrgios’ straight-sets march over No. 77 Aljaz Bedene.