Nadal roared through the opening set against Cilic, building a 5-0 lead before the Croat showed signs of life with a service hold for 5-1.
Cilic had four chances to take Nadal’s next service game but the Spaniard recovered and eventually held his servce to clinch the set 6-1.
After receiving treatment on his right ankle, Cilic promptly dropped his first service game of the second set. Though he carved out break points in each of Nadal's first three service games of the second set, he could not convert them.
Nadal broke again for a 5-2 lead and with a forehand winner claimed the match after 84 minutes. "I have to be playing well to win like this against a player like Marin, so I'm pleased with the performance," said Nadal, who withdrew from last month's tournament in Rotterdam after doctors told him he needed more rest after surge to the Australian Open final in Melbourne.
"I'm happy with my focus in important moments, saving break points with good shots," Nadal said. "I enjoyed the atmosphere and so it's great for me to be in the final."
Nadal will play the unseeded American Sam Querrey in the final. Querrey, ranked 40th, ousted Nick Kyrgios 3-6 6-1 7-5. The victory over the conqueror of top seed Novak Djokovic, continued an impressive week for the 29-year-old who had beaten world number 11 David Goffin and world number nine Dominic Thiem on his march to the semis.
"Sam is playing great,” said Nadal, who has won all four of his meetings with Querrey. “He'll be coming into the match with a lot of confidence."