PARIS — Getting her game in gear at a Grand Slam tournament, as usual, Sloane Stephens moved into the French Open’s fourth round for the third consecutive time.

Now comes the 15th-seeded American’s toughest test yet this year in Paris, a matchup against No. 4 Simona Halep of Romania. Neither has ever made it to the quarterfinals at Roland Garros.

“Obviously, as the tournament goes on,” Stephens said, “the competition gets tougher.”

She eliminated No. 22 Ekaterina Makarova of Russia 6-3, 6-4 Saturday, while Halep beat 55th-ranked Maria-Teresa Torro-Flor of Spain 6-3, 6-0 as the temperature approached 70 degrees (20 Celsius) on the sunniest day of Week 1 at the clay-court major.

“It’s really beautiful out,” Stephens said, after several days of overcast skies and the occasional rain. “I was happy I was able to play early and get the `W’ (win).”

She has shown a knack for performing far better at Grand Slams than run-of-the-mill events. This is the sixth straight major where she’s made it to the second week, a run that began with the 2013 Australian Open.

Over the last two seasons, Stephens is 21-5 (an .808 winning percentage) in Grand Slam matches, but only 32-29 (.525) everywhere else.

“If I knew what the switch was or what I was supposed to do, I would probably do it every week,” Stephens said.