Zhu Lin's hope of powering into the third round of the U.S. Open for the first time in her career was cruelly crushed after she suffered an agonizing defeat at the hands of 10th-seeded Madison Keys on Wednesday. 

The Chinese youngster started brightly, displaying a brilliant combination of net skills and agility as she raced to a 3-1 lead in the opening set. However, the 25-year-old failed to maintain momentum and allowed Keys to come from behind to wrap up the first set 6-4. 

In the second set, the 2017 finalist Keys gained complete control to take the decisive lead and kept Zhu at bay for the rest of the game to seal the victory.

Meanwhile, second seed Ash Barty fought off a stiff challenge at the end of the second set to beat American Lauren Davis 6-2 7-6(2). 

Next up for the world number two is a meeting with either Maria Sakkari of Greece or China's Peng Shuai, whose match was suspended due to the heavy rain. 

World No. 18 Wang Qiang's clash with Alison Van Uytvanck of Belgium was also scuppered by the bad weather as officials later announced that there will be no further play on Wednesday on the outside courts.

The statement said: "Due to the weather, the Wednesday day session at the U.S. Open -- Session No. 5 -- has now been canceled for all matches outside of Louis Armstrong Stadium, where matches are continuing as planned (The day session has already been completed inside Arthur Ashe Stadium)."

Fifth seed Elina Svitolina also reached the third round after knocking out Venus Williams despite a heroic defensive effort from the 39-year-old former champion. 

Trailing 5-3 in the second set, seven-times Grand Slam champion Williams saved five match points to hold serve in a dramatic 22-point game. 

Also advancing was Czech third seed Karolina Pliskova, who ousted 202nd-ranked Georgian qualifier Mariam Bolkvadze 6-1, 6-4. Pliskova, the 2016 US Open runner-up, will next face either Tunisia's Ons Jabeur or Aliaksandra Sasnovich of Belarus.

On the men's side, Reigning champion Novak Djokovic battled with a shoulder problem that hampered his backhand as he secured a 6-4 7-6(3) 6-1 win over Argentine Juan Ignacio Londero and reached the third round.

Djokovic, who had work done on his left shoulder during his pre-match warm-up inside Arthur Ashe Stadium earlier in the day, was in clear distress when he took a medical timeout while leading 4-3 in the first set.

The Serbian top seed returned to court to close out the first set and then got more treatment before Londero, in only his second main draw match at Flushing Meadows, broke him twice for an early 3-0 lead in the second.

But a determined Djokovic found his way back by winning the next five games and then, after easing through the tiebreak, had more treatment before racing home in the third.

Earlier, Roger Federer, who lost to top-ranked Djokovic in last month's epic five-set Wimbledon final, shook off another slow start to defeat Bosnian Damir Dzumhur and reach the third round.

The 20-time Grand Slam champion struggled early but battled back to dispatch 99th-ranked Dzumhur 3-6, 6-2, 6-3, 6-4 under the roof at Arthur Ashe Stadium.

The 38-year-old Swiss third seed, who also dropped the first set against Indian qualifier Sumit Nagal in his opener, answered the wake-up call after conceding the first set with 17 unforced errors.

Japanese seventh seed Kei Nishikori, the 2014 US Open runner-up, eliminated 108th-ranked American Bradley Klahn 6-2, 4-6, 6-3, 7-5.

Nishikori, who could face Federer in the quarter-finals, stumbled after seizing a 5-1 edge in the final set.

Klahn saved a match point in the seventh game, another in the 10th before holding to level at 5-5 and two more in the final game before finally falling when he sent a backhand long.

(With input from agencies)