China's Peng Shuai kicked off her 2019 U.S. Open campaign by beating American Varvara Lepchenko 6-2, 7-6 (5) and reaching the second round on Monday.

It took two years for 33-year-old Peng to return to U.S. Open. Ranked No. 167, Peng reached her first Grand Slam semifinals in 2014 U.S. Open. 

She will next face No. 30 seed Maria Sakkari of Greece, who cruised past No. 48-ranked Camila Giorgi of Italy 6-0, 6-1. 

Seven-time Grand Slam champion Venus Williams ripped China's Zheng Saisai 6-1, 6-0 in 66 minutes in the first round.

Zheng, who lifted the trophy in WTA San Jose tournament earlier, just gets on point in the first set.

"I felt like I executed my style of game the best I could," the 39-year-old American said. "I was so pumped up today, it just kind of leaked out."

Serena too strong for Sharapova in first New York meeting

Serena Williams opens her quest for a 24th Grand Slam singles crown after last year's controversial final by thrashing five-time Slam winner Maria Sharapova of Russia 6-1, 6-1 to reach second round.

Serena dominated from the start and dispatched Sharapova in 59 minutes in the showcase match at Arthur Ashe Stadium.

"Obviously I'm going against a player who has won five Grand Slams and reached the final of even more so I knew it would be tough," the American said.

"She's such a good player. When you play her, you have to be super focused. Every time I come up against her, I bring out some of my best tennis."

Australian second seed Barty overcame a horrible start to oust 80th-ranked Zarina Diyas of Kazakhstan 1-6, 6-3, 6-2.

Pliskova, a 2016 U.S. Open runner-up, edged 138th-ranked Czech compatriot Tereza Martincova 7-6 (8/6), 7-6 (7/3) after an hour and 46 minutes, finishing off the tie-breaks solidly but was humbled after exchanging six service breaks with the qualifier to open the match.

Djokovic through in straight sets

Serbian star Djokovic, who has won four of the past five Grand Slam singles titles, dispatched Spain's 76th-ranked Roberto Carballes Baena 6-4, 6-1, 6-4.

"Getting out of the blocks, it takes time for you to feel comfortable on the court," Djokovic said. "Later in the sets I was able to take advantage in the big moments and move on and that's what's important."

Djokovic, trying to become the first back-to-back U.S. Open winner since Roger Federer won from 2004-2008, will next face either American Sam Querrey or Argentina's Juan Ignacio Londero.

"I'm quite pleased with my performance and looking forward to the next one," Djokovic said.

Djokovic owns 16 Grand Slam titles and is chasing the record 20 won by Federer with Spain's Rafael Nadal on 18. Together the "Big Three" have won the past 11 Slam titles and are again heavy favorites.

Federer overcomes Nagal scare

Roger Federer has not lost in first round of Grand Slam since 2003 French Open. 

However, the five-time champion did not get off to an ideal start in this year's U.S. Open on Monday evening, giving India's Sumit Nagal several chances. But he finally came back to win 4-6, 6-1, 6-2, 6-4 after two hours and 30 minutes and advanced into the second round. 

Nagal, ranked number 190 , has never earned a tour-level victory. He only qualified for the year's final Grand Slam last week and took advantage of the opportunity in the first set of his career's biggest match. But Roger quickly cut down his errors after the first set and fought back to win.

The victory means Federer will continue his bidding for a record-extending 21st career Grand Slam title in New York. He will next face Damir Dzumhur of Bosnia, who beat Frenchman Elliot Benchetrit earlier on Monday.

(With input from AFP)