Dominic Thiem gained revenge after back-to-back final defeats with a stunning 6-4 6-3 win over seven-time Internazionali BNL d'Italia champion Rafael Nadal.
The Austrian was beaten by Nadal in his maiden ATP Masters 1000 final at the Madrid Open, having already been defeated by the same opponent at the same stage of the Barcelona Open.
But the honours belonged to the supreme Thiem in Friday's quarter-final meeting in Rome, the 23-year-old producing a heavy-hitting display that frequently had Nadal chasing shadows in his first clay-court loss of 2017.
Novak Djokovic or Juan Martin del Potro will be up next for Thiem in the last four.
Thiem – whose solitary win in this head to head came at last year's Argentina Open – was quickly into his stride, a couple of vicious one-handed backhands helping him to an opening-game break, even as Nadal landed all six first serves.
The pinpoint accuracy of Thiem's early play soon had him 2-0 up and putting pressure on the Nadal serve once more, taking the 14-time grand slam champion to deuce.
Remarkably, the world number seven simply continued to get better and Nadal initially had no answer to his opponent's power and precision from the baseline, which earned another break for a 4-1 lead.
It was then that Nadal finally had some joy against the serve, but Thiem kept his cool at 40-40, with the Spaniard forced to all corners of the court before being outdone by a thunderbolt forehand winner.
Having shown signs of life in clawing one game back, Nadal – returning to stay in the set – started with two ferocious winners and saw Thiem send one long to give the King of Clay two break points.
Although they were snuffed out, Nadal dug deep and profited from some rare Thiem errors to cut the gap, which was further reduced following a prompt hold.
Serving for the set for the second time, Thiem produced a more accomplished game to halt Nadal's fightback and move ahead.
Nadal wasted little time in testing Thiem's nerve in the second set, a deft drop shot and a powerful forehand down the line taking it to deuce in the right-hander's opening service game, though he did ultimately hold.
An increasingly animated Nadal knew he had to vary his approach and began to show a greater willingness to come to the net as he sought to disrupt the inspired Thiem's rhythm, a tactic that yielded mixed results.
One such venture forward resulted in Nadal dumping the ball into the net and he proceeded to lose the next two points to trail 15-40 on serve, before battling back for a gutsy hold.
But when he stepped up to serve at 3-3, Nadal suffered a decisive loss, one exchange leaving the crowd on their feet as Thiem raced behind the baseline and rifled a cross-court backhand past his rival.
Thiem stayed strong in the face of break points to see out a thrilling contest with a last break of his own, as Nadal wrapped up his French Open preparations with a shock loss.
IMPRESSIVE ZVEREV SETS UP ISNER SEMI
Alexander Zverev continued his promising season, which has yielded two ATP Tour titles, with a fine 7-6 (7-4) 6-1 win over Milos Raonic.
The German, who turned 20 last month, recovered from the blow of failing to serve out the opening set to win a tense tie-break against the 2016 Wimbledon finalist.
Raonic faded badly in the second set of the first meeting between the pair, the seven games taking just 28 minutes to complete.
Zverev will now face John Isner following the American's battling triumph over Marin Cilic.
Isner prevailed 7-6 (7-3) 2-6 7-6 (7-2), with the help of 21 aces, to record only his second win against the Croatian.
|Ceferin nominated for second term as UEFA president|
|Marseille have ´moved on´ from Balotelli deal|
|´Crazy´ Cheika his own toughest critic|
|McClaren defiant amid QPR woes|
|Lendl joins Zverev´s coaching staff|
|England captain Hartley ready for return|
|Buttler happy to serve up a century as England dig in at Trent Bridge|
|PSV beat BATE in Champions League thriller, Benfica held at home|
|Mkhitaryan backs Emery´s philosophy at Arsenal|
|Championship Review: Leeds go top, QPR problems mount|
|Ronaldo shares snap of ´Juventus family´|
|Aguero is the Premier League´s best foreign import, says Shearer|
|Real Madrid warned they must pay Rodrigo´s €120m release clause|
|England´s Broad fined for Pant rant|
|India on brink of victory after brilliant Bumrah halts Buttler|
|Serena Williams elevated to 17th seed at US Open|
|Kombouare signs new two-year Guingamp contract|
|Scaloni unclear on Messi´s long-term Argentina plans|
|F1 Raceweek: Gasly and Alonso restore focus at Spa|
|Nouri able to communicate, brother reveals|
|Pjanic extends Juventus contract to 2023|
|Odegaard joins Vitesse in latest loan from Real Madrid|
|Luck ´sort of happy´ with sack from Suggs|
|Manchester United´s Sanchez will ´be back soon´|
|Former Giants star Cruz announces retirement|
|RFU set Cipriani disciplinary date despite RPA complaints|
|Spalletti fined €10,000 for ´gravely offensive´ referee comments|
|IndyCar driver Wickens has spinal surgery after Pocono crash|
|Tiger: No doubt this is one of my best years|
|Vice-captain Tiger trying to remain objective in Ryder Cup conversations|
|Ronaldo won´t win Serie A by himself, warns Allan|
|Moeen sends message to England selectors with double century|
|Brunt calls time on Northern Ireland career|
|Tottenham´s Janssen sidelined after foot surgery|
|Liu Xiang breaks women´s 50m backstroke world record at Asian Games|
|Atletico Madrid winger Vitolo suffers knee ligament damage|
|Leverkusen teen Havertz aiming to emulate idol Ozil|
|Beckham to be honoured with UEFA President´s Award|
|CPS drops Hillsborough charges against Bettison|
|Who can take over from Federer, Nadal & Djokovic? Agassi backs Zverev, Kyrgios|
|´Freak incident´ rules Dragons´ Vaughan out for season|
|Kompany: Different Manchester City must not be complacent|
|Toyota withdraw appeal over Alonso´s Silverstone disqualification|
|Manchester City offload defender Denayer to Lyon|
|RPA want RFU to drop Cipriani charge|
|Cheika still the right man for Australia - Polota-Nau|
|Bolt not giving up on Manchester United dream|
|All Blacks must improve ´average´ set-piece, says Smith|
|Raiola hits back at Scholes following Pogba criticism|
|Indians top Red Sox in series opener|
|Struff stuns Cecchinato, Jarry reaches last 16|
|I´ll prove people wrong - Bolt completes first Mariners training session|
|Former champ Kvitova tops Radwanska, Pliskova ousted|
|Sad if it´s Filipe Luis´ last game for Atletico - Oblak|
|White Sox manager Rick Renteria hospitalised before game|
|Carragher: Van Dijk can become Liverpool legend|
|No timetable for Sale return from shoulder injury|
|This is a partnership - Rodgers on contract negotiations with Packers|
|Eagles QB Wentz unsure he´ll be cleared to play opener|
|Balotelli staying at Nice|
|It wasn´t a penalty, says Hodgson as Palace boss fumes at refereeing decisions|
|Salah can play much better - Klopp demands more from Liverpool star|
|Gasly to Red Bull: Vettel, Verstappen and the drivers who took their Toro Rosso chance|
|Klopp in the dark on Karius future amid links to Besiktas|
|Simeone pleased with draw after rigours of Super Cup|
|Captain Reus saves Dortmund in DFB-Pokal|
|I couldn´t care less - Klopp rejects title challenge talk|
|Ailing Bairstow keen to aid England´s unlikely victory bid at Trent Bridge|
|Redskins secure Peterson signing|
|Manchester City goalkeeper Bravo suffers ruptured Achilles|