Djokovic edged a high-quality match 7-5 4-6 7-6(2) 6-7(6) 6-3 in four hours and 43 minutes, the longest ever Wimbledon semi-final.
Del Potro looked set for the big time when at the age of 20 he beat Roger Federer, then the world number one, in the 2009 U.S. Open final.
But his career was in the balance after wrist surgery and a virtually non-existent 2010 season, and he had failed to reach another Grand Slam semi-final until this week.
"Now I go into the United States circuit up to the U.S. Open with the best motivation knowing I'm on course again," world number eight Del Potro said.
"This has been my best Wimbledon, my best matches of the year," said the Argentine, who has worked doggedly over the last two and a half years to overcome injuries and revive his hopes of breaking into the elite.
"There's a great difference between how I came into the tournament and how I leave it."
Del Potro has the game to live with the very best as he showed on Centre Court where he beat Djokovic last year to win the bronze medal at the Olympic Games.
"I always had faith that I could win," he added as he recalled saving two match points in a memorable fourth set tie-break to take the match into a decider.
"To lose like that is hard; there are matches that both players deserve to win."
The Argentine recognised that in time he would be able to look back on his performance with pride and the match as one of the great ones in a Grand Slam tournament.
"If I go on this way playing against Novak, Rafa (Nadal), the other guys (like Federer and Andy Murray), it's going to be very interesting for me, a good fight, good battles coming. I will be ready for that.
"I know this is the way to beat this kind of player. I played my best tennis on a grass court from a long time, but it was not enough to beat the number one in the world."
Del Potro enjoyed support from the majority of the crowd with his excellent tennis and fighting spirit against a tenacious and, at times, inspired Djokovic.
"What I experienced in there (on the court) was special, it had been a long time since I had played like that.
"I think the crowd enjoyed the match a lot. Amazing, I really enjoyed watching them as well. When I was down at moments in the match, I saw the crowd, they were clapping me, and that helped me a lot for sure.
"For me it was fantastic, because losing two sets to one against the number one in the world, if the crowd doesn't cheer me, it's tough to come back.
"They helped me a lot to fight, to keep trying, to keep going. Of course I'm sad now, but in couple of days I will see how big the match was."
- Sports & Recreation
- Novak Djokovic
- Juan Martin del Potro
- Roger Federer