The win helped him extend his incredible run at Roland Garros to 66 wins and just one defeat over 10 years.
Dominic Thiem is the only man who has gotten the better of him on clay in the last two years.
"Unfortunately, he could get destroyed", Bresnik said. "I was very scared".
Nadal called it "not even a dream" to gather 11 titles in Paris, saying it was "impossible to think of something like this".
"If you tell me seven, eight years ago that I will be here ... having this trophy with me again, I will tell you that is something nearly impossible", Nadal said.
The Spanish world number one took his Roland Garros win-loss record to a jaw-dropping 86-2 as he captured his 17th Grand Slam title.
For Thiem, playing in his first Slam final, it was a tremendous letdown for a player who is the only man to have beaten the Spaniard on clay in the last two years. "What you did and what you are doing is the most outstanding thing that any athlete can achieve in sport".
"He said "you have got to play as if you're going to be in the finals, with the same sort of aggressive play" and Andy went on to win majors".
If Thiem is, as he is widely regarded, the second best clay-court player in the world then he probably has a few more of these pummellings to look forward to at least until Nadal, 32, finally calls it a day.
With a celebrity audience - including actors Hugh Grant and Tim Roth as well as French stars Marion Cotillard and Jean Dujardin - watching, Nadal flew out of the blocks.
Others highlighted Nadal's remarkable record at Roland Garros since first winning the title there in 2005.
"And in general. game-wise it was a good game".
The Austrian - competing in his first grand slam final after a pair of semifinal showings in Paris - needed to win the first set to have any realistic opportunity of ending Nadal's reign.
Thiem stayed with Nadal in the early going on a cloudy and steamy afternoon; the temperature was 77 degrees (24 Celsius), the humidity approached 70 per cent.
It was a match told in break points.
That was swatted away with Nadal's double-handed backhand, though, and the second set duly went the way of the favourite.
Thiem was under the cosh, saving four break points in the first game of the third set before Nadal inevitably broke for 2-1.
It was more of the same in the second, as Nadal won the opening three games in quick time to take a commanding lead he would never relinquish.
It was his most one-sided final win since allowing Federer just four games in the 2008 final. Nadal had another massage at 5-2 and he ended Thiem's ordeal on his fifth match point when the Austrian returned long.