Intro:

Laura Robson continued her remarkable US Open on Friday as she defeated French Open champion Li Na.

Script:

This is turning out to be an excellent US Open for Laura Robson.

The 18-year-old forced Kim Clijsters into retirement earlier this week and now she has the scalp of another Grand Slam champion.

Robson defeated Li Na 6-4 6-7 6-2 to become the first British woman to reach the fourth round of a Grand Slam in 14 years.

And the world number 89 was a worthy winner against the number nine seed.

Defending champion Sam Stosur should be worried about Robson.

Stosur will meet the teenager in the last 16 after completing a straight sets victory over American Varvara Lepchenko.

And Novak Djokovic progressed to the third round with ease following a 6-2, 6-1, 6-2 win over Rogerio Dutra Silva of Brazil.

Maria Sharapova wasn't hanging around in the 90 degree heat as she thrashed home favourite Mallory Burdette 6-1 6-1 to set up a fourth round encounter with Nadia Petrova.

2009 champion Juan Martin del Potro ended American Ryan Harrison's hopes in four sets but it is Laura Robson who is the talk of the US Open on Friday.