I don’t know what I did wrong for God to make me endure both of today's women's quarterfinals at Indian Wells, but it probably was a lot.

Nevertheless, here we are after two wild and wooly matches best characterized by these stats: Flavia Pennetta and Sloane Stephens surpassed Li Na and Dominika Cibulkova in the combined unforced errors tally, 112 to 110. But Li and Domi won the battle of total break points, 32 to 29.

Yet somehow, Pennetta’s 6-4, 5-7, 6-4 win over Stephens was the match with the more clear and orderly narrative. For from the very start it shaped up as a challenge to the Italian veteran’s self-confidence. In Stephens, the well-traveled 32-year old Pennetta was going up against one of the rising young players in the WTA, and facing her on the 20-year-old’s home turf.

At best, Stephens is a puzzling character who has a very specific type of talent. She can’t possibly be as nonchalant as she often looks, because there’s no way she would have climbed to No. 18 in the rankings if she were. She’s just one of those athletes who, despite being remarkably quick and gifted with great anticipation, seems to move only when forced, and then not very happily.

To some degree, this tendency to sluggishness hurts Stephens' chances. She’s successful despite rather than because of it. We saw exactly why that is so through most of the first two sets, during which Stephens looked flat and, at times, disinterested in the proceedings. Pennetta took full advantage. She kept her feet moving and kept Stephens from exploiting her less reliable forehand side.

Unlike the Li/Cibulkova match, this one had a very clear turning point. Pennetta kept a tight rein on her service games through the first two sets despite struggling to get her first-serve conversion rate above the 40 percent mark. She broke in the seventh game of the first set and made it stick.

The second set commenced with an exchange of breaks, followed by a Stephens hold for 2-1, When the young American broke Pennetta for 3-1, it seemed she might be turning things around. But Pennetta broke right back for 2-3.

Pennetta held the next game, and then Stephens survived a long game (and three break points) to take a 4-3 lead. Stephens appeared to have her opponent right where she wanted her, but then Pennetta produced a brave, quick hold and Stephens turned in one of the most artless games of the match. Playing as if her soles were glued to the court, Stephens made four ghastly errors to allow Pennetta to break for 5-4.

This seemed the moment of reckoning for Pennetta, and she shrank from it. After jumping to a 30-15 lead she lost control of her nerves, choked badly, and ended up stoning a couple of forehands to give back the break. It was such a painful experience that the distracted Pennetta lost both of the next two games to leave the match even at a set apiece.

It seemed that Stephens had Pennetta on the run at that point, and to further complicate matters, clouds and a vicious, swirling wind moved in from the west. Stephens handled that ambient challenge better, and in the blink of an eye she had run her string of games won to six—and a 3-0 lead in the third set. In fact, Stephens had a pair of break points in the very next game, but the badly wounded Pennetta managed a hold that probably saved her the match.

After the hold, things turned again—this time, for good. A shanked groundie, double fault, and cross-court backhand error left Stephens at love-40. She played two good points, but made a forehand error off a service return on the third break point to give up the game for 3-2. A quick hold by Pennetta, and suddenly it was 3-all.

This dedicated push by Pennetta seemed to break down Stephens. She was broken in the 10th game at love, thanks to a Pennetta pass and three self-inflicted errors. With a second chance to serve out the match, Pennetta took full advantage. It took her four match points, but she wrapped it up to book a place opposite Li in the semis.