Djokovic and Del Potro walked on Arthur Ashe Stadium court with the Billie Jean King National Tennis Center still buzzing over the controversial women's final on Saturday, won by Japan's Naomi Osaka after Serena Williams incurred three code violations.
Aged just 20, Del Potro defeated Rafael Nadal and Roger Federer in successive matches to win the 2009 US Open, and the world No 3 was determined to stay competitive, staying firm following a gritty hold in the opening game of the next set. Djokovic also leads Del Potro 14-4 in their head-to-head encounters.
It is his 14th Grand Slam title, which ties him with Pete Sampras for third on the all-time major singles titles list behind Federer's 20 and Nadal's 17.
Djokovic and del Potro embrace.
"When I had my surgery I could truly understand what Juan Martin was going through when he had surgeries that kept him away from the tour for two or three years", added Djokovic.
"I'm so happy to be playing the final against this magnificent idol".
The Argentine was forced to dig deep at the beginning of the second set, saving two break points as the 31-year-old peppered his weaker side with cross-court backhand-to-backhand rallies.
The disappointment on Sunday belonged to a teary Del Potro who was back in a Grand Slam final for the first time since the big Argentine won his one and only title at Flushing Meadows in 2009.
Djokovic was soon 3-1 up in the second set before Del Potro carved out his first break point of the match to level at 3-3.
"To the support of the loved ones, my kids, my wife, my small team of people that has been there with me through hard times as well", added the Serb who underwent elbow surgery after the Australian Open in January".
In the immediate aftermath of Djokovic's victory, he embraced del Potro at the net in a heartwarming show of class and respect between the friends and foes.
Never was that more apparent than the game that stood out on this evening: with Djokovic serving while down 4-3 in the second set. But when Djokovic faced three break points in the following game, an epic that required 22 points to settle, he saved them all.
"Of course I'm sad I [lost]", del Potro said.