The world number two performed admirably to upset the Croatian 6-4, 6-3.
Carlos Alcaraz, the defending champion, celebrated his 20th birthday by reaching the Madrid Open final on Friday, comparing himself to "a bull" in his straight sets victory over Borna Coric.
The world number two performed admirably to upset the Croatian 6-4, 6-3.
In Sunday's final, he will face Germany's Jan-Lennard Struff, the world number 65, who was knocked out in qualification before getting a reprieve.
Alcaraz claimed he used some of the inner determination that helped him win his first Grand Slam title at the US Open in New York last year.
"There was a moment when I repeated what I said at the US Open, that I'm a bull and that I can do it," he explained.
In a close opening set, Alcaraz broke for a 3-2 lead and served it out to reach his fourth Masters 1000 final.
In the second set, he broke for 2-1, and when world number 20 Coric promptly came back, he broke again for a 3-2 lead, which he secured.
When Coric went long, Alcaraz clinched the match with another break, ensuring he reached the final after only lost one set against Emil Ruusuvuori.
The top seed was entitled to celebrate his triumph with a birthday cake provided by the event administrators.
The main setback for Alcaraz was the announcement that fellow Spaniard and 22-time major winner Rafael Nadal would miss next week's Italian Open due to injury.
Nadal has not played since the Australian Open in January owing to a hip ailment and is now a severe doubt for the French Open in three weeks, where he has won 14 times.
The entire world wants Nadal.
"I hope to see him at Roland Garros 100 percent." "The world wants to see him at 100 percent," Alcaraz remarked.
Struff, 33, advanced to his second career final after overcoming Russia's Aslan Karatsev in qualification last weekend.
Struff, who was given a spot in the main draw due to injury pull-outs, avenged that loss in Friday's semi-final.
He fought back from a set down to defeat 121st-ranked Karatsev 4-6, 6-3, 6-4 to become the first "lucky loser" to reach a Masters final.
Struff, who had previously finished runner-up in the final in Munich in 2021, won on a fifth match point.
In his two-hour, 19-minute victory, he hit 37 winners, including 15 aces.
"It's amazing," Struff exclaimed. "I played in one final before in Munich, but there was no crowd because of COVID."
Struff and Alcaraz have fought twice before, with the German winning in straight sets in 2021 at the French Open and the flamboyant Spaniard prevailing in five sets at Wimbledon last year.
'I have no choice but to go for it."
"We played an amazing match at Wimbledon, and I was very close to beating him, but he pulled off unbelievable shots," Struff explained.
"This is going to be unique. This is in Madrid, Spain. He's probably 20-0 on Spanish clay courts, so it'll be a tough match. I have to go for it or I won't have a chance."
Struff, who defeated fifth-ranked Stefanos Tsitsipas in the quarter-finals, became the third lucky loser to reach the Masters 1000 semi-finals, following Thomas Johansson in Toronto in 2004 and Lucas Pouille in Rome in 2016.
On Saturday, the women's final in Madrid will be played between world number one Iga Swiatek and world number two Aryna Sabalenka.