Nadal is hoping to win his 11th French Open title this weekend but Del Potro stands in his way of a spot in the final.
The world No 1 was on a magnificent 37-set winning run at Roland Garros until Diego Schwartzman caused him a scare in the quarter-finals.
Rain interrupted that clash and when it resumed Nadal came out firing by coming from a set down to claim victory.
Meanwhile, Del Potro had to beat Marin Cilic and John Isner to reach this stage and he will be hoping to pull off a huge shock.
And Nadal knows he will be in for a difficult afternoon where defensive play is not an option.
“Del Potro has achieved great victories this year,” Nadal said.
“He has fantastic potential. Aggressive game from the end of the court, the baseline. And I have to play aggressively.
“If I play defensively and I don’t take intensity, I will lose.”
Rafael Nadal vs Juan Martin del Potro LIVE
Rafael Nadal 6-4 6-1 2-0 Juan Martin Del Potro*
12 points in a row for Nadal now. The crowd on Philippe Chatrier sound very disgruntled.
They like every one else was hoping for much more from this semi-final.
Rafael Nadal 6-4 6-1 1-0 Juan Martin Del Potro*
Worst possible start to the set for Del Potro as he is broken to love.
This set could be over very quickly.
*Rafael Nadal 6-4 6-1 Juan Martin Del Potro
Nadal is now one set away from reaching his 11th French Open final and he holds serve comfortably.
Huge mountain for Del Potro to cliimb now.
Rafael Nadal 6-4 5-1 Juan Martin Del Potro*
More errors from Del Potro and poor shot selection from the Argentine. Nadal gets two set points but Del Potro saves them both.
And he stops the heavy bleeding to avoid being bageled.
Nadal will serve for the set.
*Rafael Nadal 6-4 5-0 Juan Martin Del Potro
Now seven games in a row as Nadal holds to love. Del Potro is not even running for some balls at the moment.
Rafael Nadal 6-4 4-0 Juan Martin Del Potro*
Nadal wants the double break and he gets it. SIX games in a row now and Del Potro already looks a beaten man.
This is not the contest we hoped for.
*Rafael Nadal 6-4 3-0 Juan Martin Del Potro
Del Potro earns himself a chance to break back immediately. But Nadal has been ice cold all today and once again shuts out the Argentine.
Beginning to look ominous for Del Potro.
Rafael Nadal 6-4 2-0 Juan Martin Del Potro*
In no time at all, Del Potro falls to 0-40. And another unforced forehand errors sees Nadal break.
Very poor game from the Argentine.
*Rafael Nadal 6-4 1-0 Juan Martin Del Potro
You can sense Del Potro frustration at not being able to break down Nadal’s defences.
Nadal is taking the heat coming from Del Potro’s racket and responds with interest to take the lead.
Rafael Nadal 6-4 Juan Martin Del Potro*
Breathtaking pass by Nadal to get himself to 0-30. But Del Potro responds with another huge forehand.
However Nadal gets his first break points, which are of course set points. Del Potro saves the first.
Vintage Nadal defence keeps him in the point before Del Potro puts a backhand into the net.
The Argentine can’t believe he lost that set.
*Rafael Nadal 5-4 Juan Martin Del Potro
Two more break points for Del Potro. Nadal saves the first with a dropshot. Then Del Potro goes wide with a wild forehand.
And Nadal forces Del Potro to serve to stay in the set after winning a duel at the net with sharp hands.
Rafael Nadal 4-4 Juan Martin Del Potro*
Del Potro holds to love.
*Rafael Nadal 4-3 Juan Martin Del Potro
A more comfortable game for Nadal as he gets Del Potro on the run.
That will be his best tactic for success today.
Rafael Nadal 3-3 Juan Martin Del Potro*
Before coming out Del Potro speaks to the trainer and receives some painkillers which is a relief.
Del Potro then duly holds his serve again.
*Rafael Nadal 3-2 Juan Martin Del Potro
More Del Potro pressure on the Nadal serve to move to 0-30. But Nadal fights back again and escapes.
Rafael Nadal 2-2 Juan Martin Del Potro*
Del Potro is looking to dominate with his forehand and he wins this game with a huge shot down the line.
The Argentine does pull up short with a leg problem. Something to keep an eye on there…
*Rafael Nadal 2-2 Juan Martin Del Potro
Three break point chances for Del Potro. But Nadal is always at his best when his back is against the wall.
He saves all three as Del Potro is unable to make any impact.
That will be a confidence booster for the world number one.
Rafael Nadal 1-1 Juan Martin Del Potro*
Comfortable hold for the Argentine.
*Rafael Nadal 1-0 Juan Martin Del Potro
Early scare for Nadal as Del Potro puts him on early pressure on serve.
But the Spaniard hangs on to take the lead.
3.00pm: Both players are just putting the final preparations together now with some practice serves.
Should be underway any moment…
2.55pm: Del Potro and Nadal just making their way on court now – expecting the clash to get underway in about 10 minutes time.
2.45pm: Thiem has just revealed on court that he will be ‘studying’ both Nadal and Del Potro during this match in preparation for Sunday.
“I think it is very important to regenerate now and to have a good practice tomorrow,” Thiem said.
“I need to keep up my good level and watch the semi-finals now.
“I will study my next opponent a little bit and then full power on Sunday.”
2.30pm: Good afternoon and welcome to a warm and muggy Roland Garros where we are just awaiting Rafael Nadal on Court Philippe-Chatrier.
Dominic Thiem has just booked his place in Sunday’s final after beating Marco Cecchinato in a thrilling match 7-5, 7-6, 6-1.