Rafael Nadal moved to within one win of a 10th Barcelona title on Saturday when he swept past Argentina's Horacio Zeballos 6-3, 6-4 in the semi-finals of the clay court event.
World number five Nadal, who captured a 10th Monte Carlo Masters last weekend, will face Dominic Thiem in the final after the Austrian stunned world number one Andy Murray 6-2, 3-6, 6-4.
Nadal, 30, who will be playing in his 106th career final on Sunday, won the Barcelona title in 2005-09, 2011-13 and 2016.
Despite his straight sets win, on a centre court which is named after him, Nadal was far from pleased with his week's work in the Catalan capital where rain has made the conditions heavy.
"In weeks like this, the one who manages to cope with the conditions we've had, which have been significantly different (than normal), is the one that survives," said the Spaniard.
"They aren't the best conditions for me and against Zeballos it wasn't easy at all. He took me out of my comfort zone, particularly in the first few shots of the rally which is what did damage."
Nadal will take a 2-1 career record over Thiem into Sunday's final with all their meetings having come on clay.
Thiem fired 41 winners and six aces as the fourth seed advanced to his 12th ATP World Tour final with a first win over Murray.
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Austrian tennis player Dominic Thiem returns the ball to British tennis player Andy Murray during their ATP Barcelona Open match in Barcelona on Saturday AFP
Murray squeezed past Albert Ramos-Vinolas in a three-hour encounter on Friday and looked flat-footed as Thiem roared through the opening set with three breaks of serve in just over half an hour.
The Scot edge the second set with the only break, but still looks well short of the player that rose to number one on a spectacular run at the end of last year as he struggles for form and fitness after an elbow injury.
Thiem had to battle back from a break down in the third, but constantly put pressure on the Murray serve and broke another three times in the deciding set to seal his place in the final.
However, having accepted a late wildcard to play in Barcelona, Murray believes the match practice will do him good with Masters series events in Madrid and Rome to come ahead of next month's French Open.
"I got three matches in three days against all different players," said Murray.
"To play two hours today after three yesterday, will be good for me."