The Spaniard, who has never won the Shanghai showpiece, is chasing a seventh title in a brilliant season and a hat-trick of triumphs on the trot, having been crowned US Open and China Open champion in recent weeks.
Dimitrov raced in to unleash a backhand victor for a break point in the fourth game of the final set, but Nadal thwarted him again and claimed the decisive break to lead 4-2 before sealing yet another win. Albert had to dig deep in the third game of the second set, saving 4 break points, but he couldn't do the same next time around, as Cilic broke him in game 5, converting his 7th break point since the start of the match.
While a Nadal-Federer final looms, Argentina's Juan Martin del Potro could ruin the script, as he did at the U.S. Open where he defeated Federer in the quarter-finals when a semi-final between the two greats looked likely.
Dimitrov hit 42 winners to 32 from Nadal, but the sixth seed was unable to prevent a 10th defeat to Nadal in 11 meetings between the two after he was unable to break the favourite's reliable serve in an entertaining quarter-final.
Ramos-Vinolas lost his serve in game 6 to trail 4-2 and that was all Marin needed to close the set, losing just one point in his last 2 service games and delivering a set by 6-3 in 38 minutes.
Cilic said consistency was key. "They are quite clear for me and I also am a little bit more consistent this year in serving performances".