Flushing Meadows (New York), Aug 28 (IANS): Chinese ninth seed Li Na and defending champion Samantha Stosur reached the US Open tennis second round Monday with easy victories.

Li, the 2011 French Open champion, snatched a 6-2, 6-3 win over Britain's Heather Watson but had to endure a marathon rain break before sealing the triumph, reports Xinhua.

Stosur had an impressive start to her title defense, crushing Croatian Petra Martic 6-1, 6-1 in just 51 minutes.

Li, who had lost in the first round on her last two visits, will face Australia's Casey Dellacqua, who ousted Lesia Tsurenko also 6-2, 6-3, for a place in the last 32.

"I really feel happy. Last few years, I always (lost the) first round," said Li.

"I say, you have to do for yourself. You really have to win the first match."

Li, buoyed by her recent Montreal's final berth and Cincinnati triumph, led 6-2, 5-3 when rain forced the players off court for over two and a half hours.

On their return, Li needed just three minutes to wrap up the match, taking victory when Watson, the 2009 US Open junior champion, netted a backhand.

Li gave credit to her new team and her confidence-building Cincinnati win.

"I was in the final of Montreal and I won in Cincy, so I am feeling I got a lot more confident. Also I got a new coach (Carlos Rodriguez). My physio has always done a good job taking care of my body so I can stay healthy on the court," she said.

The 28-year-old Stosur, who won her first grand slam title at Flushing Meadows last year, lost in the first round at this year's Australian Open and London Olympics while she was beaten in round two at Wimbledon.

"I think probably today I carried on from exactly how I was feeling last year," said Stosur, who upset Serena Williams in last year's final.

"Hopefully that's a good omen. As far as first rounds go, I was very happy with today."

Expectations and pressure have got the better of her at times but she looked perfectly at ease against Martic, winning the first 19 points of the match before double-faulting to allow the Croatian her first point.

A couple of seeded players suffered early exits. Sixteenth seeded Sabine Lisicki of Germany lost to Sorana Cirstea of Romania 4-6, 6-2, 6-2.

Czech Kristyna Pliskova stunned 18th seeded Julia Goerges of Germany 7-6(4), 6-1.

Another Czech Lucie Hradecka breezed past 27th seeded Medina Garrigues from Spain 6-3, 6-3.

Last year's quarterfinalist Andrea Petkovic of Germany lost to Swiss Romina Oprandi 6-2, 7-5.