MIAMI, Fla.—It was a two-set WTA match, but it lasted just seconds shy of two-and-a-half hours. The winner hit a dazzling 44 winners—fully 31 more than the loser—yet she was constantly in danger and had to fend off three set points before closing it out. The loser didn’t hit a single ace, but posted an 84 percent first-serve conversion percentage.

By now, you know there’s only one player who can leave those marks on the stat sheet: Italy’s finest, WTA No. 7 Sara Errani. On Wednesday in Key Biscayne, she fought one of the guerilla wars for which she’s become famous, pushing No. 3 seed Maria Sharapova to the brink—maybe not the brink of a loss, but certainly the brink of a nervous breakdown.

You’d think it would have been a lot easier to dispatch a woman who entered the match 0-25 against Top 5 players, and 0-11 against the Top 2. But Errani represents a special brand of torment for the likes of Sharapova. By the time Sharapova completed her 7-5, 7-5 quarterfinal win at the Sony Open, her signature high-pitched shriek had morphed into a prolonged, deep growl, but the dachshund attached to her jowl still wouldn’t let go.

When Errani was broken in this match, she often broke back. When Sharapova belted an inside-out winner, Errani often responded by immediately forcing her into an error on the next point. This was a match loaded with blown (or dismissed) 30-love leads, deuces, and a staggering 29 combined break points; each woman converted a third of them—four by Errani, six by Sharapova.

These fluctuations had less to do with the wind in Miami or the windpipe of either player than the way they match up: Sharapova goes for broke, Errani tries to make her opponents go broke. Errani’s game plan is to impel her opponents to hit one more shot than they’re capable of successfully making, while Sharapova’s shtick is to hit one fewer than what most people would consider appropriate for winning a point. Basically, it’s a square peg against a round hole, and each woman is capable of frustrating the other.

“I feel very lucky that I’m through,” Sharapova said when it was over. “She had her chances to win that second set, so who knows what would have happened? She’s extremely difficult. She makes you work. And she doesn’t have the height, doesn’t have the power, but her ability to get so many balls back, to stay consistent—and to do it over and over again. . . she’s able to do those things very well when she has time.”

Aye, there’s the rub in this match. As Errani said: “I try to play my game, try to stay there, try to run, try to play to have more time to hit the ball and play my game. I try to move the ball but with her the points are very fast and short—and I like another style of game. With Maria, you don’t have time to do what you might with another player. For sure you have tactic, but for her that’s not very important because she makes the point short.”

In the immortal words of former heavyweight champion Mike Tyson, “Everybody has a plan until they get punched in the face.”

For a good part of the first set, though, many of the punches Sharapova threw hit nothing but the court—the portion of it that lies outside of the lines. It was windy and bright, and let’s face it, the eyes of 6’2” Sharapova are a lot closer to the sun than those of the diminutive (5’4”) Errani’s.

Yet one of Sharapova’s unheralded achievements is the ability to slough off those double faults that can cause a player to unravel and continue to attack the ball with undiminished relish. Time and again today, she’d crack a double fault and follow it up with a prodigious winner before the titters and groans in the crowd faded.

Those errant serves have a modest dividend, in that they play in an opponent’s mind as well. If Sharapova just hit a double fault at deuce, wouldn’t you nudge over to the ad-side thinking, “Wow, one more of those and I’m a happy camper.”

On top of that, some of Sharapova’s misfires can be put down to a mindset that’s just as willing to assume risk at the service notch as at the baseline. As Errani observed: “When she serves second serves, 90 or 95 miles (per hour), she can make double faults. But you have to count also the points when she do a second serve that go in, and win the point for her because it is so flat and powerful.”

One of the great improvements in Sharapova’s game in recent times has been her ability to step in and tag the big forehand, especially the inside-out variety, when one of those stinging 95 M.P.H. second serves is returned. When the ball is a blur, just getting it back into play is the mandate. The desire to powder the ball if it does cross back over the net has grown in Sharapova.

As the first set wore on, Sharapova overcame her fear of serving. She clung to a one-break lead until Errani ran the table on Sharapova’s serve in the 10th game to eliminate the lead. But Sharapova broke again in the very next game, after a rare Errani double fault brought up deuce. Sharapova jumped on her next opportunity and hit a cross-court forehand winner for break point, then traded warp-speed groundstrokes with Errani until the latter drive a down-the-line forehand out. Sharapova served it out, ending the set with an ace and a service winner.

The second set continued the pattern of long games and intense exchanges that only a jackrabbit-quick player like Errani can prolong into rallies. The women exchanged four straight breaks starting with Errani serving at 2-2, and it began to look like Errani’s relentless consistency was beginning to take its toll on Sharapova. The match teetered on brink, ready to fall on either player’s side, when Errani had three set points in the ninth game.

Sharapova brushed aside the first one with a cross-court backhand winner. She addressed the next two with a pair of stone-cold inside-out forehand winners. That left her at deuce, and she secured the hold with a successful smash and a backhand volley winner. Errani surely suffered a letdown after that impressive escape, for she was broken at 15 in the next game, and Sharapova went on to serve it out with no further drama.

Mulling over that critical ninth game, Sharapova said: “I don’t feel like I should have been in that position (three break-points down). It’s great that I got myself out of it. But you know, I was up 30-love on my serve and those are the type of games that against these type of players you need to buckle down and win.”

This was the second time in as many matches that Errani had set points against Sharapova, only to fall short by a hair. Is there any doubt that she’s the best 0-26 challenger to the top players?