PARIS — Well, that’s settled: 19-year-old Sloane Stephens is bumping herself up to first class for the flight home from the French Open, whenever that might be.

That extra-comfy trip back to Coral Springs, Fla., is among the benefits the American is looking forward to after reaching the fourth round at Roland Garros by beating Mathilde Johansson of France 6-3, 6-2 yesterday.

Another perk?

“Now I’m going to have more Twitter followers,” explained the bubbly Stephens, the only teenager left at the fourth, and most successful, Grand Slam tournament of her nascent career.

With her ever-improving game, athletic parents — her late father, John Stephens, was the 1988 NFL Offensive Rookie of the Year with the Patriots; her mother, Sybil Smith, was Boston University’s first All-American in women’s swimming — and infectious personality, Stephens might just be the next big thing in U.S. tennis.

Stephens will face her toughest test yet when she faces reigning U.S. Open champion and 2010 French Open runner-up Sam Stosur, who defeated Nadia Petrova 6-3, 6-3, with a quarterfinal berth at stake.

Also on the women’s side, second-seeded Maria Sharapova defeated Ayumi Morita of Japan 6-1, 6-1 in a match postponed a day while Ana Ivanovic fell to Sara Errani, 1-6, 7-5, 6-3.

For the men, top-ranked Novak Djokovic extended his Grand Slam win streak to 24 matches by beating Nicolas Devilder, 6-1, 6-2, 6-2, and Roger Federer, the 2009 champion, was pushed to four sets for the second straight match before defeating Nicolas Mahut 6-3, 4-6, 6-2, 7-5.