Massive blasts from Juan Martin del Potro sent puffs of chalk flying, fans gasping, and Novak Djokovic sprawling across the lawn in determined pursuit.

Playing his first Wimbledon semifinal, an explosive del Potro displaced pieces of the lines and fought off two match points in a gripping fourth-set tiebreaker, but could not dislodge the world No. 1 from reaching his destination.

Defending resourcefully and striking boldly on crucial points, Djokovic outdueled del Potro, 7-5, 4-6, 7-6 (2), 6-7 (6), 6-3, in an outrageously entertaining Centre Court shootout that was the longest Wimbledon men's semifinal in history.

This was a pulsating, four-hour and 43-minute piece of Grand Slam theater exceptional in its quality and character as both men, who faced off a year ago at SW19 in the Olympic bronze-medal match (won by del Potro), doggedly pushed each other to elevate their  games.

The jolting pace of del Potro's flat drives sometimes rushed Djokovic into impulsive replies—he was missing his normally trusty two-hander down the line in the early stages—and the top seed was over anxious trying to hit the finishing shot. Sliding into a full-stretch backhand winner down the line got Djokovic's creative juices flowing in the 12th game, after 11 straight holds. He changed the tempo shrewdly, softening up the big man with slower slice backhands before bolting a powerful backhand cross-court for set point. A del Potro inside-out forehand strayed as Djokovic snatched the 55-minute first set on the strength of a single service break.

Playing with a hyper-extended left knee wrapped in tape, del Potro teetered facing four break points in the sixth game of the second set, but stood tall in holding for 3-3. Racing forward while unleashing a scream that sounded like a Samurai cry, del Potro caught up to a dipping drop shot and flipped a forehand pass cross-court for 0-30, then threw his arms up in air, rousing the crowd to erupt. A rattled Djokovic sprayed a forehand and it was triple break point. Del Potro, who looked staggered five minutes earlier, smacked a backhand down the line and high-stepped to his chair, pumping his first with his first break and a 4-3 second set lead, while a dazed Djokovic stared at the ground like a man wishing he could re-trace his steps after straying from a familiar path.

Superb shot-making under pressure saw del Potro fought off three set points serving at 5-6 of the third set. In the tiebreaker, Djokovic used the first serve-and-volley of the day to level at 2-all, then relied on his elastic reach to dig out a lob. The eighth-seeded Argentine slapped a routine smash into the net to concede the mini-break as Djokovic closed the breaker on a six-point run, reflexing a backhand winner to take the 62-minute third set.

The two exchanged breaks in the seventh and eight games of the fourth set. In the fourth-set breaker, both men lost unsuccessful challenges on balls that struck the baseline, and when Djokovic cracked an ace he had a 4-1 lead. Then, an inside-out forehand gave Novak double-match point. The adventure of a point that followed ended with Djokovic nudging a desperate lob long—and del Potro throwing his arms up as if trying to wave the ball's flight long—on the first match point. On the second, del Potro stepped forward and calmly curled a forehand winner cross-court. Empowered, he smacked a backhand winner down the line, then crushed a cross-court backhand to bring the virtually the entire Centre Court crowd to its feet in a rush of excited sound.

At that point, you had to wonder about del Potro's ailing knee and Djokovic's wounded psyche: Would lingering nerves from losing a fifth-set lead and falling to Rafael Nadal in an epic Roland Garros semifinal haunt Djokovic, and could del Potro's troublesome knee withstand the prospect of a final set with no tiebreaker? Both answered the call.

The 2011 champion has a well-deserved reputation as the game's most dangerous returner, but bold serving saved him at times today. Djokovic served 69 percent, denied five of seven break points, and hit 22 aces to four for the 6'6" Tower of Tandil. Facing break point at 2-all in the fifth set, Djokovic crouched low and cracked a backhand winner up the line as the shot that failed him earlier saved him. Del Potro saved a break point to hold for 3-all, but Djokovic used the drop shot beautifully to tire del Potro in the eighth game, then broke with some dazzling defense for 5-3. Juan Martin covered his eyes with his hand and cringed seeing his forehand sail long, while Novak sucked air in the shade of the back wall, then stepped up to serve it out.

Stress spiked to dizzying heights with Djokovic serving for the final at 30-all when his shot hit the top of the tape and sat up. Del Potro crunched a forehand for break point, then his return skimmed the tape and dribbled over, but Djokovic did well to reach the dipping ball quickly and calmly lifted a tricky drop shot winner for deuce. A big serve down the middle brought the top seed to match point number three—a full 50 minutes after his last match point. Eyes fixed on the ball, Djokovic drilled his backhand down the line to close a match for the ages.

They extended each other in a thriller that had everything from scalding winners to fortuitous net cords to an acrobatic Djokovic diving across the court and unrelenting del Potro twice nearly landing up in the laps of fans in the front row pursuing shots. No matter where you sat, you couldn't just watch this match, you had to feel it. If you're like me it left you buzzed and breathless.

!IBM Stat of the Match: Del Potro brought heavy artillery to this semifinal, but Djokovic actually hit more winners than the Argentine, 80 in all.

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