Diego Schwartzman beat Denis Shapovalov 6-4 5-7 7-6(4) on Sunday to book an Italian Open final date with Novak Djokovic on Monday.
Schwartzman, who knocked out Nadal in the quarter-finals on Saturday, will break into the top 10 of the rankings if he beats Djokovic in the title clash.
The Argentine bested the young Canadian in a dramatic back and forth match that ended in a tense third set tiebreak.
Djokovic, meanwhile, was made work hard by Casper Ruud in blustery conditions before the world number one got past the unseeded Norwegian 7-5 6-3 in the earlier semi-final.
