What do you tell yourself when you’re about to serve for the match against Serena Williams at the French Open? In Garbine Muguruza’s case, you keep it simple:

“OK, don’t lose your mind,” the 20-year-old said as she stepped to the line to try to close it out.

Muguruza did more than keep her head together. She used it well enough to throw the No. 1 seed off her game and hand her the most lopsided loss of her Grand Slam career, 6-2, 6-2, in just 64 minutes.

“She played really well,” a disappointed and slightly stunned Williams said afterward, “she played really smart.”

Muguruza’s game plan was the height of simplicity: Hit the ball right down the middle, with as much pace and depth as possible.

“I wanted to be so aggressive from the beginning,” she said afterward. “Don’t give her angles, so she doesn’t make me run.”

It was a plan that might have been cribbed from Ana Ivanovic, who beat Serena by going as big as possible, as early as possible, at the Australian Open this year. But it was perfectly suited to Muguruza’s style—a long-legged six-footer, her strength is hitting with power; her weakness, as she hinted, is retrieving. She knew she couldn’t play defense against Serena, and she never really did.

Of course, it’s one thing to have a game plan, and quite another to execute it against a 17-time Grand Slam champion. Muguruza was virtually flawless, especially with her returns and backhands, which seemed to be laser-guided to a spot about a foot in front of the baseline. Even when Williams was serving, she was on her heels. It’s rare to beat Serena, but it may be even rarer to break her five times in the process.


Roland Garros: Muguruza d. S. Williams

Roland Garros: Muguruza d. S. Williams

Serena was flat to start, and as she admitted later, she never adjusted to the straight-ahead Muguruza attack. Williams had a little bit of success in the first set trying to move Muguruza wide, but mostly she tried to hit through her. The result was 29 unforced errors for Serena against just eight winners. Each time it appeared that Muguruza might be ready to get tight, Serena helped her out by going for too much and missing.

At the start of the second set, rather than making the Spaniard play and possibly start to think about what was transpiring, Serena slapped four straight service returns out. Only at 1-3 in the second did Williams try to slow the pace and gather herself, but that only made things worse. She double faulted twice in that game and shouted, “I can’t serve.”

Afterward, Serena dismissed the possible excuses the press tossed her way—no, she wasn’t injured, she said; and no, the conditions hadn’t been especially tricky.

“She played really great,” Serena said, “But it’s good because I’m going to go home and work five times as hard so I never lose again.”

Most amazing about Muguruza’s performance was the way it ended. With her casual stride and head held high, she looked collected rather than nervous—that’s what a good game plan, and a little bit of time in the zone, can do for you. Muguruza saved her biggest serve of the day for the final game, and held at love. She had kept her mind, and used it well.