Maria Sharapova of Russia hits a return to Heather Watson of Great Britain during their match at the US Open tennis tournament in New York, August 29, 2011. [Photo/Agencies]

Former champion Maria Sharapova survived a first-round scare before roaring back to beat talented British teenager Heather Watson 3-6 7-5 6-3 at the US Open on Monday.

"No doubt that was one of the toughest (first-round) matches that I've had," the third seed and 2006 winner said.

The 19-year-old Watson, US Open junior singles champion two years ago, took advantage of erratic play from the Russian by extending the rallies and appeared poised for an upset at 5-5 in the second set before Sharapova raised her game.

Hitting with added ferocity deep into the corners, Sharapova moved her 104th-ranked opponent from side-to-side and eventually wore her out in two hours 34 minutes on Arthur Ashe Stadium court.

"She is a great up-and-coming player," said Sharapova, who produced 41 winners, primarily off her forehand, but also committed a whopping 58 unforced errors. "She played really smart in the first set and I was making too many errors."

Urging herself on, world number four Sharapova held from 30-30 to grab a 6-5 lead in the second set and then induced Watson to net a backhand to push the match to a third set.

The 24-year-old Sharapova raced to a 3-0 lead in the third set but Watson battled back to 4-3 with a service break.

The three-times grand slam winner then put the hammer down, closing the match when Watson sailed a backhand long.

The victory improved Sharapova's record in three-set matches this year to 12-0, but it might have heralded a coming-out party for the young Briton.

"I had a lot of fun today in my match," said Watson. It's what I want to do. I want to be out there on the big courts playing the top players."

The New York crowd, always enamoured with the underdog, cheered on Watson, who was surprised by all the support.

"I absolutely loved the atmosphere today," she said. "I thought everyone was going to be supporting Maria.

"I had a lot of support. I heard some people calling me Cinderella, all sorts of stuff. And just when they were chanting my name, I kind of got the goosebumps."

Sharapova next plays Anastasiya Yakimova of Belarus, a 6-0 4-6 6-3 winner against Noppawan Lertcheewakarn of Thailand.

Heather Watson of Great Britain returns a shot to Maria Sharapova of Russia during their match at the US Open tennis tournament in New York, August 29, 2011. [Photo/Agencies]