Miami - Juan Martin del Potro raised the roof as he came from behind to beat Milos Raonic 5-7, 7-6 (7/1), 7-6 (7/3) and power into a Miami Open semi-final clash with American John Isner.
Roared on by a partisan crowd, del Potro rallied after losing the first set to finally wear down the Canadian in two hours and 53 minutes of relentless drama.
There was little difference between these two big hitters, but it was the Argentine who held his nerve when it counted to book a last-four encounter with Isner on Friday.
"I love to play in matches like this," a visibly weary del Potro said after his 15th straight match win.
"We both played well, the difference was perhaps that I just played better in the tie-breaks.
"I am tired now, but at least I have a day off to prepare for Friday. It's going to be important that I recover physically and mentally because that was a real battle."
Del Potro came into the match owning the hottest streak on the ATP tour with 20 match wins this year.
The Argentine's return to form has delighted his fans in Miami, where they packed the main stadium once again to cheer their hero ever closer to winning the "Sunshine Double" of Indian Wells and Miami on the heels of his triumph in Acapulco.
Raonic, the big serving Canadian, had other ideas.
The pair met in the Californian desert just three weeks ago with 2009 US Open champion del Potro winning 6-2, 6-3, but 25th-ranked Raonic was on his game from the off.
The first set went with serve until del Potro double-faulted on set point to silence the crowd.
Their fears worsened as sixth-ranked del Potro called for the trainer, although after a lengthy discussion with officials no treatment was given and the second set began.
It was similarly neck and neck with both players hitting powerfully from the baseline.
Del Potro badly needed to break a player who arrived at this last eight encounter having held in all 28 service games as well as saving five break points in his three straight-sets triumphs.
Attempting to stay alive in the match, del Potro almost suffered a freak injury when, racing to reach a Raonic passing shot, he leaped over a hoarding and into the photographer's pit at the side of the court.
He needed time to recuperate but emerged unscathed and was able to send the second set into a tie-break.
Del Potro raced to a 5-0 lead and sent his fans wild by sending the match into a decider.
The first four games all went against serve as Raonic was broken for the first time in the tournament.
Del Potro finally held for 3-2 and Raonic was left to serve at 5-6 to keep his hopes alive and so it went into a final tie-break.
- Isner dominates Chung -
Del Potro carved out a 5-2 lead, a position of strength from which he was finally able to see the match out.
Isner will, however, be a difficult nut to crack with the American recovering from an early season slump to play some of the best tennis of his career.
His destruction of South Korean Chung Hyeon 6-1, 6-4 was impressive considering the 14th seed arrived in South Florida having won just two matches all year.
The big-serving 32-year-old American fired 13 aces to dispatch 19th-seeded Chung in only 68 minutes.
"I played extremely well and every match I have gotten better and stronger," Isner said.
"The conditions were perfect for me. The way the ball bounces, the court isn't too fast, so it's great for me. I have played well here before but I am delighted to get this far."