The odds were against Sam Stosur in the final of the Southern California Open on Sunday. Not only had she won just three finals before in the course of her 14-year career, she had never beaten her opponent, Victoria Azarenka, in their seven meetings.

Stosur overcame both sets of bad odds by doing one thing extremely well: playing the break points. She faced 12 of them on her serve, and won 11. On Azarenka’s serve, Stosur earned five break points, and won four.

The world No. 13 has never been known as a psychological rock, but she was at her best with her back against the wall on her serve today. When she needed an unreturnable on a break point, she found it. She won those points with flat aces up the T, big kicks out wide, and even a change of pace second serve that Azarenka overhit. Up 3-1 in the first, Stosur faced five BPs in that game before holding. By doing so, she turned what might have become a see-saw, no-one-can-hold adventure into her match to lose. She did the same in the first game of the second set. Azarenka again reached break point; if she had won it, a turnaound might have begun. But Stosur hit another ace, held, and kept her momentum intact.

This was Azarenka’s first event since suffering a knee injury early at Wimbledon, and the rust showed. Ornery and off her game from the beginning, she made 32 errors against just 11 winners, and never took command of the rallies even when she had a chance—she won just 28 percent of points on her second serve. By the middle of the second set, her frustration had overwhelmed her usual fighting spirit. It was far from a perfect match by Stosur, who made 29 errors and hit 20 winners, but she was so much better when it mattered that she ended up winning by the lopsided score of 6-2, 6-3.

Earlier in the day, 2009 U.S. Open champion Juan Martin del Potro began his road to New York with a title in Washington, D.C. Stosur, the 2011 winner at the Open, followed by doing the same. Should we start talking about Sam the way we’re talking about Delpo, as the scariest sleeper in Queens? In her case, I’d take it one match, and one tournament, at a time. Winning them both on Sunday was breakthrough enough for now.