Sloane Stephens on upward trajectory

The first time I saw Sloane Stephens live was on Court 1 at Roland Garros last year, in the famed Bullring against Samantha Stosur. It was a terrific test for Stephens, a talented American for whom great things are forecast. It was a fourth-round match, and thus Stephens had entered the business end of the tournament. She had beaten Ekaterina Makarova (who had knocked out Serena Williams at the Australian Open) in the first round, and, to reach her first quarterfinal of a major, she would have to go through Stosur, a top-10 player who defeated Serena in the 2011 U.S. Open final.

As the sun cast shadows on the Bullring, 19-year-old Stephens fell in straight sets, 7-5, 6-4, but what I remember was her losing much more than Stosur winning. She was not intimidated by Stosur's pace, no small thing considering Stosur's serves and forehands are among the sharpest in the women's game.

The second time I saw her play was a few weeks later at Wimbledon, against another highly ranked player, Sabine Lisicki. Lisicki took that third-round match in three sets, 7-6 (3), 1-6, 6-2, the death blows coming in the decider, when Stephens squeaked and squawked her way through unforced errors and frustration. Still, with a big serve (Lisicki is one of the bigger servers on tour, and Stephens matched her at about 117 mph) and forehand, Stephens had numerous chances to take control of the first set, only to be undone by inexperience.

Maybe Stephens is arriving faster than expected. She is ranked a career-high 25th -- the third-highest American, behind Serena and Varvara Lepchenko -- but is seven full years younger than 26-year-old Lepchenko, 11 years younger than Serena and 13 years younger than No. 26 Venus Williams. She lost 4 and 4 to Serena in Brisbane but has wins this year over 14th-ranked Dominika Cibulkova (who recently beat No. 5 Angelique Kerber in Sydney) and Laura Robson, a player she beat in the third round of the Australian Open.

The American women are showing promise. Seventeen-year-old Madison Keys (ranked 135) beat No. 17 Lucie Safarova and reached the quarters in Sydney before losing in three sets to Li Na, and Serena has already won a title this year, in Brisbane. The Americans have five women -- Serena (3), Lepchenko (20), Stephens, Venus and Christina McHale (35) -- in the top 40, and Stephens, who has career wins over Maria Kirilenko, Sara Errani, Cibulkova and Francesca Schiavone, might be the player best positioned for a breakout in at the Aussie.

Her latest challenge comes Monday in Melbourne, when Stephens faces Bojana Jovanovski. And then a potential clash with Serena. And you can bet the tennis world will officially take notice.