NEW YORK (AP) — Novak Djokovic is through to the third round at the U.S. Open and will use some of the time until then getting more treatment on his left shoulder.

Djokovic fought through trouble with the shoulder to beat Juan Ignacio Londero 6-4, 7-6 (3), 6-1.

The defending champion was treated by the trainer multiple times in the match and appeared in trouble when he fell behind 3-0 in the second set. But he battled back to take it in a tiebreaker and had an easy time in the third set.

The No. 1 seed wouldn’t reveal much about the nature of the injury in his post-match interview.

Novak Djokovic of Serbia returns a shot during his Men’s Singles second round match against Juan Ignacio Londero of Argentina on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Clive Brunskill/Getty Images)

Serena Williams has avoided what would have been her earliest loss in 19 appearances at the U.S. Open.

Williams came back from a set down in the second round at Flushing Meadows to beat 17-year-old American Caty McNally 5-7, 6-3, 6-1.

The only time Williams ever has been beaten as early as even the third round in New York was in her tournament debut all way back in 1998 — when she was just 16 herself.

The following year, Williams won the first of her six U.S. Open championships. McNally hadn’t even been born yet.

Serena Williams of the United States reacts during her Women’s Singles second round match against Catherine McNally of the United States on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Katharine Lotze/2019 Getty Images)

Second-seeded Ash Barty barely avoided getting pushed to a third set and got past Lauren Davis of the United States 6-2, 7-6 (2) to reach the third round at Flushing Meadows.

Barty won the French Open in June and is trying to get past the fourth round in New York for the first time.

Ashleigh Barty of Australia returns a shot during her Women’s Singles second round match against Lauren Davis of the United States on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Matthew Stockman/Getty Images)

Venus Williams of the United States reacts during her Women’s Singles second round match against Elina Svitolina of the Ukraine on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Al Bello/Getty Images)

Venus Williams needed a little pick-me-up on a rainy day in New York.

It takes more than caffeine to beat Elina Svitolina, though.

Williams had a resurgence after some coffee was sent her way after dropping the first set against the No. 5 seed, but Svitolina charged back and eventually beat Williams 6-4, 6-4 in a second-round match.

Williams fought off five match points in a 22-point game to hold her serve before Svitolina eventually ended it on her sixth chance, improving to 13-3 in Grand Slam matches this season.

Roger Federer once again came back from a set down to advance at the U.S. Open, beating Damir Dzumhur 3-6, 6-2, 6-3, 6-4.

Roger Federer of Switzerland reacts during his Men’s Singles second round match against Damir Dzumhur of Bosnia and Herzegovina on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Elsa/Getty Images)

The second-round match was very much like the opener for the third-seeded Federer, who dropped the first set against qualifier Sumit Nagal before cruising the rest of the way. Federer again stepped up his game against the 99th-ranked Dzumhur, winning 77 percent of his first-serve points and blasting 58 winners, more than double that of his opponent.

The five-time U.S. Open champion is now 19-0 in second-round matches at Flushing Meadows and moves on to play the winner of the match between 25th-seeded Lucas Pouille and Daniel Evans.

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