World number one Rafael Nadal was dumped out of the Shanghai Masters on Saturday by inspired Argentine Juan Martin del Potro, who blew the Spaniard away with a relentless display of brutal hitting to set up a final against Novak Djokovic.
The giant Del Potro, fresh from winning the Japan Open, went into the semi-final at the Qizhong Tennis Center trailing 8-3 in head-to-heads, but rocked Nadal with a double break in the first set and kept up the pressure to win 6-2, 6-4.
Earlier, top seed Djokovic swept aside Jo-Wilfried Tsonga 6-2, 7-5 to earn the chance to defend his title.
Nadal has enjoyed one of the best seasons of his career, winning 10 titles including the French Open and the US Open, and came into the match with all eyes on yet another showdown with Djokovic.
But the 13-time Grand Slam champion was given the run-around by the sixth seed, who launched a sustained and blistering all-court attack from the start, achieving the rare feat of out-hitting his illustrious opponent.
Dominating from the baseline on both forehand and backhand sides, Del Potro raced into a 4-0 lead in the first set as Nadal desperately searched for a foothold.
A single break was enough in the second set for the inspired Argentine, who hit a total of 28 winners and 31 unforced errors, landing 80 percent of first serves.
Nadal, by contrast, failed with all six of his break point opportunities.
In the first semi-final, Tsonga landed just 46 percent of first serves in an ultimately one-sided first set, and despite an improved showing in the second he cracked in the 12th game as Djokovic completed a straight-sets win.
"I think I raised my game today compared to last night's match," said Djokovic, who lost his cool midway through the second set over a couple of line calls before he found his focus again.
"Of course, I would wish to get even a better performance tomorrow for the most important match this week. But we'll see."
The Serbian, 26, broke to love in the second game, helped by two double faults, and had a break point to establish a 4-0 lead as Tsonga struggled to gain a foothold.
The seventh seed dug deep, securing a break of his own to peg Djokovic back to 3-2, but his form then dipped again and he lost the next three games.
A more balanced second set involving a break apiece looked to be heading towards a tie-break, but the Serb secured the decisive break, claiming victory on his second match point.
Nadal and Djokovic are among three players who have already secured their places at next month's elite World Tour Finals, featuring the season's top eight players.
Tsonga and Del Potro are among those hoping to secure one of the remaining five places.