NEW YORK — Lleyton Hewitt displayed the same shots and grit that earned him a US Open trophy and the No. 1 ranking a dozen years ago.
Now 32, and ranked 66th, Hewitt came back to surprise 2009 champion Juan Martin del Potro, 6-4, 5-7, 3-6, 7-6 (7-2), 6-1, Friday night in the second round at Flushing Meadows.
Also, Novak Djokovic and Andy Murray, who have met in three of the last four Grand Slam finals, each took a step forward Friday, shaky at moments and sensational in others, in second-round victories. The top-seeded Djokovic faced two early set points, while defending champion Murray had to go four sets.
‘‘I don’t know how many years I've got left in me. I keep getting asked the question,’’ Hewitt said in an on-court interview. ‘‘I'm just pumped to get out on this court and try to put on a great show.’’
The 4-hour, 3-minute match was the ninth time in the past 10 years that two past US Open title winners faced each other in New York. Hewitt was involved four times, losing the other three.
He won the US Open in 2001 by beating Pete Sampras in the final, and then added a Wimbledon title the following year. But he has been troubled by a series of injuries more recently and lost in the first round at four of his last six Grand Slam tournaments.
‘‘A couple years ago, when I had a couple foot surgeries, I didn’t know if I was going to play tennis again,’’ Hewitt said.
Against the sixth-seeded del Potro, who is 24, the Australian repeatedly scrambled along the baseline to stretch for terrific groundstrokes.
While the men hit about the same number of winners — Hewitt had 42, del Potro 41 — the biggest difference was in the unforced error department. Del Potro finished with a whopping 70 errors, 27 more than Hewitt.
‘‘The wrist is not the way I'd like, but it’s not an excuse,’’ said del Potro, who did not try to defend his US Open title in 2010, because of a left wrist injury that required surgery. ‘‘Now I have a few days to rest.’’
Hewitt next faces 102d-ranked Evgeny Donskoy.
‘‘My favorite tournament, and I go home tomorrow,’’ del Potro said. ‘‘That’s the worst part of this sport.’’
Leonardo Mayer, ranked 81st, ran Murray all over the court, but the third-seeded Brit excels at chasing down shots. Murray won the last five games for a 7-5, 6-1, 3-6, 6-1 victory.
After pulling out the first set in a tiebreaker, Djokovic needed less than an hour to close out his victory. The 2011 champion beat 87th-ranked Benjamin Becker, 7-6 (7-2), 6-2, 6-2. Djokovic was playing in Arthur Ashe Stadium, where the wind often swirls to players’ frustration.
Another Grand Slam winner, Li Na, also showed championship form earlier on Ashe. This time, her opponent, Laura Robson, looked very much like a teenager.
The fifth-seeded Li avenged her third-round upset loss to the young Brit at last year’s US Open, winning, 6-2, 7-5, at the same stage at Flushing Meadows.
Australian Open semifinalist Sloane Stephens, seeded 15th, beat fellow American Jamie Hampton, 6-1, 6-3. Hampton, at No. 23, was seeded at a Grand Slam tournament for the first time.
Defending champ Serena Williams beat Yaroslava Shvedova, 6-3, 6-1, in the nightcap at Ashe.
Third-seeded Agnieszka Radwanska and No. 9-seeded Jelena Jankovic pulled out tough straight-set victories.
Wimbledon runner-up Sabine Lisicki, seeded 16th, won’t be making a run after she was eliminated by Ekaterina Makarova, 6-4, 7-5.
Fifth-seeded Tomas Berdych beat Denis Kudla of the US, 7-6 (7-3), 7-6 (7-3), 6-3. American Tim Smyczek, ranked 109th, reached the third round at a Grand Slam tournament for the first time. He edged 73d-ranked Alex Bogomolov Jr. in five sets, needing nearly four hours to win, 3-6, 7-6 (8-6), 2-6, 6-4, 6-4.