Schwartzman, who came back from two sets down to beat Kevin Anderson in the last 16, rediscovered his form, but it came too late to save the set as Nadal served it out in a marathon eighth game on his second set point after saving four break points.
"If he would have won the tie-break, he would (have been) full power, for sure, in the third set".
In greenback terms that comes out at $2.6m, making it the smallest winner's prize of the year's four Grand Slam events and almost $1m less than the richest tournament the US Open which paid its 2017 winners - Nadal and Sloane Stephens - $3.7m each.
The second set tie-break proved to be decisive as the Italian player squandered three set points, having recovered from a 6-3 deficit, reports Efe.
The injury-prone Argentine had a discussion with Dr. Bernard Montalvan during the changeover, with Nadal leading 3-2 in the first set.
Nadal certainly lived up to his "King of Clay" nickname in Friday's semifinal against Juan Martin del Potro, crushing the sentimental favorite 6-4 6-1 6-2 to reach a record 11th final at Roland Garros.
Nadal is now just the second man to reach 11 finals at the same Slam‚ equalling Roger Federer's mark at Wimbledon. But after the loss, I go a little bit down mentally and physically.
Nadal, a 16-time Grand Slam champion, claimed his 85th win here against just two losses after weathering a big-hitting opening from 2009 US Open victor Del Potro to win 6-4, 6-1, 6-2.
"If I'm facing Rafa, I'm not the one who has the pressure", he said.
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It would make sense for him to come here because it would take all of the pressure off of him playing-wise. As this point, the suitors - the Lakers, 76ers, Rockets, Spurs and of course, the Cavs - seem clear.
The No. 1-ranked Nadal compiled a 35-20 edge in winners while making only 19 unforced errors Friday.
"I was in the same seat", he said after watching Nadal beat Dominic Thiem in straight sets, 6-4, 6-3, 6-2. Stephens won last year's U.S. Open; Halep is 0-3 in major finals.
Nadal has not lost at Roland Garros when taking the first set and that record did not look like coming under threat as he continually rebuffed Thiem's attempts to make inroads into his serve, taking the second courtesy of an early break.
Once Nadal stole the opener with a break in the 10th game, it was one-way traffic.
Just 45 percent of Thiem's first serves went in, compared to Nadal's 65 percent.
Nadal is looking as comfortable as ever on the Philippe Chatrier court where has previously won the title 10 times.
Nadal acknowledged that Thiem has been a "very complex" opponent.
Although at times during the first set against Del Potro, especially when he was 0-40 down at 1-1 and 15-40 down at 4-4 it looked as though he might be in for a real scrap. Nadal claimed the final two points of that game in contrasting fashion, ripping a cross-court backhand that left the crowd gasping and deftly hitting a volley off a tricky net cord.
The forecast says there is a chance of rain.