Federer and Jankovic hit top gear

By Pritha Sarkar

NEW YORK (Reuters) - Roger Federer leapt into the fourth round and Jelena Jankovic zoomed in on a maiden grand slam crown at the U.S. Open on Sunday when the title favourites discovered their sweet spots at Flushing Meadows.

After a week of lukewarm performances, four-times champion Federer turned on the heat with a masterful 6-3 6-3 6-2 destruction of Czech 28th seed Radek Stepanek.

Women's world number two Jankovic looked to be heading for another long workout but found her range to end the plucky challenge of Danish teenager Caroline Wozniacki in the fourth round with a 3-6 6-2 6-1 victory.

Austria's Sybille Bammer survived an exhausting three-hour marathon to knock out 12th seed Marion Bartoli 7-6 0-6 6-4.

As temperatures soared on Louis Armstrong Stadium, an ailing Bartoli struggled with stifling conditions and even had her blood pressure checked by a trainer during a changeover.

While Bartoli wilted under sunny skies, Federer flourished.

In his first two matches, the Swiss master had fallen well short of proving his title credentials as he piled up 66 unforced errors and converted only 11 of 28 break points.

On Sunday, he dazzled Stepanek and 23,000 wide-eyed fans on Arthur Ashe Stadium court when his game clicked into overdrive.