Add in the trophies he has earned at six Australian Opens, one French Open and four Wimbledons, most recently in July, and the 31-year-old Serb pulled even with Pete Sampras for the third-most majors among men, trailing only Roger Federer's 20 and Rafael Nadal's 17.
"I was hoping he was going to be here, but he's not," Djokovic said about Sampras.
"He's my idol. Pete, I love you."
Federer lost in the fourth round in New York, while Nadal retired from his semifinal against del Potro because of a bad right knee. That put the 29-year-old Argentine back in a grand slam final for the first time since his breakthrough nine years ago, a comeback for a guy who had four wrist operations in the interim.
"I'd just like to congratulate Juan Martin ... for still having faith, for still having belief in himself," said Djokovic, who gave his pal a hug at the net, and then went over to console del Potro as he wiped away tears at his sideline seat.
"I believe he'll be here again with the champion's trophy. I really do."
Del Potro spoke this week about the low point, in 2015, when he considered quitting the sport.
But supported by a dozen or so friends from back home, whose "Ole!" choruses rang around the arena, he climbed up the rankings to a career-high No 3 by thundering his 160km/h forehands and 215km/h serves.
Those produce free points against so many foes. Not against Djokovic, who always seemed to have all the answers.
Djokovic was better than del Potro on their many lengthy exchanges, using his trademark body-twisting, limb-splaying court coverage to get to nearly every ball, sneakers squeaking around the blue court in Arthur Ashe Stadium, where the roof was closed because of rain.
Never was that more apparent than the game that stood out: with Djokovic serving while down 4-3 in the second set. They went back and forth, through eight deuces and all those break opportunities for del Potro, until he slapped one forehand into the net, and another sailed wide.
The tiebreaker was resolved thanks to more del Potro miscues on his forehand side, as he looked more and more fatigued.
He made one last stand by breaking and holding for 3-3. But that was that.
When it ended, thanks to a three-game closing run by Djokovic, he flung his racket away and landed on his back, arms and legs spread wide.
"Of course I'm sad I [lost]," del Potro said. "But I'm happy for Novak and his team. They deserve to win."
It is the fourth time Djokovic has won multiple majors in a season.
• Ashleigh Barty and CoCo Vandeweghe won the women's doubles final, beating Timea Babos and Kristina Mladenovic 3-6, 7-6, 7-6.
The 13th-seeded team of Barty and Vandeweghe knocked of the No 3 and No 1 seeded teams en route to their first grand slam doubles title as a team.
Vandeweghe, niece of former NBA star Kiki Vandeweghe, became the 17th American woman in the Open era to win the tournament title. The pair won US$700,000 for their win.
- AP
