Carlos Alcaraz took his time to warm up, but finished in red-hot form as he beat Jaime Faria to reach the third round at the US Open.
World number 72 Faria took the first set off the still ring-rusty Alcaraz, who is playing his first tournament since suffering the wrist injury which kept him out of the French Open and Wimbledon.
But the defending champion found his rhythm and won the next eight games to take the second set and roar 2-0 ahead in the third.
Spanish second seed Alcaraz allowed his Portuguese opponent to win just five more games in a commanding 4-6 6-0 6-3 6-2 victory.
Alcaraz would become the first man in the open era to successfully defend a grand slam title on all three surfaces if he wins the US Open.
Combustible Russian Andrey Rublev almost threw a racket into his own face as he crashed out to Daniel Merida.
Rublev, the 23rd seed, had just dropped serve in the fourth set when he sat down and angrily bounced his racket into the ground.
The racket reared up and spun towards Rublev’s face, forcing the 28-year-old to duck out of the way, before sheepishly getting up and fetching it from behind his chair.
Spaniard Merida went on to clinch a 6-7 (3) 6-2 6-4 6-4 and a place in the third round.
American eighth seed Ben Shelton needed four sets to get past Poland’s Hubert Hurkacz, while highly-rated Spanish youngster Rafael Jodar was knocked out.
The 19-year-old, who started the season ranked 165 and has soared to world number 13, was brought crashing back down to earth with a 6-2 6-1 6-1 defeat by Chinese lucky loser Yunchaokete Bu.
Mariano Navone backed up his dramatic win over an ailing Novak Djokovic by knocking out former Wimbledon finalist Matteo Berrettini in four sets to set up an all-Argentinian third-round clash with Tomas Martin Etcheverry.