NEW YORK -- Seven years ago, a 20-year-old from Argentina lit up Arthur Ashe Stadium with an array of sizzling strokes capable of taking your breath away.
Juan Martin del Potro brought down Roger Federer, ending a 40-match win streak, in a five-set final that suggested many more major titles.
That one, glorious effort remains del Potro's only Grand Slam championship. Four wrist surgeries, untold misery and large doses of heroic fortitude later, he was back Thursday night, desperately trying to rejuvenate his career.
Technically, based on the bare rankings, del Potro was the underdog against No. 19 seed Steve Johnson, a diligent player who has improved himself every year since turning professional five seasons ago.
In truth, the near-capacity crowd seemed torn between rooting for the American -- or the feel-good story of 2016.
In the end, the good feelings continued, as del Potro eased away with a 7-6 (5), 6-3, 6-2 victory that sent him sailing into the third round.
"It's amazing, the stadium, amazing the atmosphere," del Potro said in his on-court interview. "I am so happy to be playing tennis again after my third surgery on the [left] wrist.
"I'm trying to play as I did in 2009, but it's not easy because I'm older."
Johnson, No. 22 among ATP World Tour players, is only one spot behind highest-ranked American John Isner, something that might surprise casual fans of the game.
In the first round, the 26-year-old Californian authored a monumental escape after trailing Evgeny Donskoy 6-4, 6-1, 5-2 -- serving at love-40. He rallied for his second career comeback from a 0-2 deficit, winning the last three sets 7-6 (2), 6-3, 6-3. He saved a total of six match points.
In Thursday's pivotal first set, Johnson saved four break points in one game. In the tiebreaker, he erased a 5-1 deficit with four straight points of his own. But eventually, the sheer weight of del Potro's shot (and some relentless defending) seemed to wear down Johnson.
"It's tough when you don't play your best tennis against a guy like Juan," Johnson said. "I didn't feel nervous at all. I just didn't execute what I needed to execute."
Del Potro emerged this year, modestly enough, advancing to the third round at Wimbledon. But at the Olympics in Rio de Janeiro, the No. 141-ranked player was a revelation, scalding No. 1 Novak Djokovic in the first round and taking it all the way to the gold-medal final before losing to Andy Murray.
When the USTA announced it was giving the 6-foot-6 del Potro a wild card into the tournament, Johnson said, "It may make a lot of American fans upset" if he faced an American in the opening round. Turns out, it was an American in the second -- Johnson.
This was the first-ever night win at the US Open for del Potro, but his 0-for-3 record came at the hands of Djokovic (twice) and Lleyton Hewitt, both champions here.
"I lost the three night matches, but I won the most important one, against Roger in the 2009 final," del Potro said. "That will be in my heart for the rest of my life."
A second title here, considering everything he has gone through, might be even more heart-wrenching.