PARIS—At her best, Jelena Jankovic’s defensive skills and counterpunching abilities can pose many interesting questions for Maria Sharapova. Now coming out of an extended slump, Jankovic showed she’s still capable of such interrogations—even if Sharapova can come up with all the answers, as she did today in a French Open quarterfinal.

Sharapova won the match, which lasted just over two hours, 0-6, 6-4, 6-3. Throw the first set out and it was a whale of a match, choc-a-bloc with rallies that were both long and skillful, superb serves and returns, and well-managed emotions that helped produce that rarest of WTA matches—one in which there were just two service breaks in the decisive set.

You would not have guessed that this butterfly would ultimately develop out such a wooly and ugly caterpillar. Jankovic held a long game to start the match and, surprisingly, lashed out to break serve with ease in the second game. Jankovic, who’s seeded No. 18, rolled through the next four games as well. Sharapova never even got to break point against Jankovic’s serve, and the surprising thing was that Sharapova didn’t serve all that badly—she made 78 percent of her first serves, and she hit but one double fault—but her ground game, and especially her backhand, was wretched. She hit 20 errors in that set alone.

Sharapova began to find her range in the second set. She had a break point in the first game, and Jankovic handed it to her with a double fault. In the next game, Sharapova belted four winners, three of them with that recently broken backhand wing. It was a signal that her form was turning around and improving. The good news for the spectators was that the improvement in Sharapova wasn’t accompanied by a decline in Jankovic’s game. Thus, over the next two sets we saw some of the best rallies of the tournament.

When Sharapova seized another Jankovic service game for a 4-1 lead, it seemed she might leave the Serb in the rear view mirror. But Jankovic, showing a degree of toughness many of us had forgotten she possessed, kept her composure. She managed to earn one break back in the eighth game, and won the next one to trail by just 4-5. But Sharapova uncorked three unreturnable serves and forced a backhand error to take the second set before things got too dicey.

The women settled in for a battle of holds distinguished by wonderful shotmaking for the next six games. Sharapova’s defense looked better than it ever has, and her ability to hold her own—and then some—in so many quality rallies against as mobile and precise and opponent as Jankovic was impressive. For her part, Jankovic served better than she has in ages. In fact, her second serve looked like less of a liability than ever before. And that dangerous down-the-line backhand—“It’s the shot that pays my bills,” she said the other day—has stabilized.

But in second-seeded Sharapova, the resurgent Jankovic was up against the defending champ and the most able of competitors. Thus it was Jankovic who ultimately blinked, while serving the seventh game of third set. From 15-30, Sharapova hit a terrific forehand passing shot that nulled Jankovic’s excellent approach, and she then nailed the return of an excellent serve so hard that JJ barely got the racquet in the way of the ball.

Sharapova wasn’t out of the woods yet, despite her 4-3 lead. Jankovic had a break point in the next game, which Sharapova wiped out with a powerful drive volley—but not before watching Jankovic lob back two of her smashes. But Sharapova held thanks to two backhand errors by Jankovic, and added an anti-climatic break in the final game to move on the semifinals.

Stat of the Match: Sharapova had just two double faults and just one ace (which was one more than Jankovic).