For this would have been the world No3’s first competitive appearance since knee surgery seven weeks before. That his return was scheduled against a man fighting back from his own long-standing injury problems—and del Potro had also denied the Swiss on some of his biggest stages—was a cherry on Miami’s cake.
In the event, Federer’s place was taken by lucky loser Horacio Zeballos, who was ranked 112 and looking for his first tour-level win of the year. The 30-year-old then delivered another blow to the tournament, beating one of Miami’s favourite players, 6-4, 6-4, in just an hour and 20 minutes.
Also of concern, for Potro and his fans, was that the big Argentine, playing in just his first event this year, and having played nothing at all in 2015 after losing in the first round here, was clearly having more problems with his left wrist.
For the left-handed Zeballos, it was not too difficult to steer away from the formidable del Potro forehand and focus on the double-handed backhand that has become such a liability. Del Potro has repeatedly resorted to using sliced single-handed backhands to protect that wrist, and he called for the trainer after the first set. It was to no avail: Zeballos, who dropped only nine points on serve through the entire match and offered up not a break point, broke at the first opportunity in each set, and sealed his first Masters match-win since this same tournament in 2014, 6-4, 6-4.
He will now play the other unseeded player in this quarter, fellow left-hander Fernando Verdasco, who beat No28 seed Jeremy Chardy, 6-4, 6-4.
The only seed to fall in the top quarter of the draw was No21 Feliciano Lopez, though Miami’s slow conditions have always been a problem for the serve-and-volley veteran. This was his sixth first-round loss in Florida, taking his record to 11-14 on its violet courts.
It ensured, though, that at least one of the ATP’s #NextGen stars made it through. The 20-year-old Yoshihito Nishioka is one of 10 players born in 1995 or later who set out in the Miami draw, via qualifying, and with No24 seed Nick Kyrigios yet to play, the young Japanese is the only other one among the 10 to remain.
Two of the youngest new stars did put up stern fights after coming through Round 1 openers, however.
No52-ranked Alexander Zverev, who had match point against Rafael Nadal last week in Indian Wells, followed his two-tie-break victory here against Michael Mmoh with a two-tie-break loss to Steve Johnson, 7-6(9), 7-6(3), despite saving all four break points he faced and serving 14 aces. Johnson now meets Tomas Berdych, who enjoyed a walkover courtesy of the stomach virus picked up by Rajeev Ram.
The tall and very promising American teenager Taylor Fritz flagged after a gripping and high-quality first set against No8 seed David Ferrer, and could not maintain his early challenge into the second set. He lost 7-6(6), 6-1 to the Spaniard, who now faces Lucas Pouille.
But what of the British #NextGen man, Kyle Edmund, who battled impressively past Jiri Vesely 6-4, 5-7, 7-6(6) to score his first main-draw win in Miami?
Unfortunately, his second match was always going to be a test of unparalleled difficulty, against top seed and defending champion, Novak Djokovic.
The remarkable Serb was targeting a 25th win from his last 26 played in Miami. His victories in 2014 and 2015 took his tally to five titles, and there was little sign of his powers fading—here or anywhere else.
Djokovic has already compiled a 22-1 match run this year, winning Doha, the Australian Open and Indian Wells. How he was targeting his fourth back-to-back Indian Wells-Miami double, one of the biggest challenges in men’s tennis—and few doubted he would pull it off. After all, since the start of last year, Djokovic has put together a 104-7 record via 20 tournaments, with 14 titles from 18 finals.
Against Edmund, who admitted beforehand that it was an honour to play against the champion for the first time, Djokovic raced from the blocks for a 4-0 lead. The Briton, though, caused a stir by pulling a break back in what was just his 14th tour-level match and only his second against a top-10 player.
Edmund continued to hit strongly, especially with his explosive forehand, but not once did his big serve score an ace against the near-impenetrable defensive ability of the Serb, the Djokovic drew more and more errors from Edmund’s racket—35 by the end of the 80-minute contest.
Djokovic held his lead to take the first set, 6-3, and was in control for most of the second, breaking twice and offering not a single break point in return, 6-3.
Edmund told BBC Sport: “I felt like I put my game out there and tried to play some aggressive tennis. At points it worked, but at times I need to find the balance.
“[Djokovic] is always there constantly, every point. He doesn’t give you many cheap points. That’s why he’s so tough to beat. It’s one thing watching on TV but now to actually experience it, you can see why.”
Djokovic, however, was impressed: “He definitely does have the potential to step up and get himself to the top of the men’s game.”
Djolovic next plays Joao Sousa, the lowest-ranked seed in the draw, who beat Vasek Pospisil, 6-7(1), 7-6(5), 6-2.
MORE: The latest football news
MORE: The latest tennis news
BIOGRAPHY: Cesc Fabregas