New York: Putting aside concerns, if any, about his wrist injury, Novak Djokovic beat Pole Jerzy Janowicz, 6-3, 5-7, 6-2, 6-1 in the first round of US Open at Arthur Ashe Stadium, here on Monday.

With the win, Djokovic improved his Flushing Meadows record 58-9, and has put himself on track to maintaining an impressive streak at the US Open in which he has reached the final four or better every year since 2007.

Meanwhile, Rafael Nadal, the two-time US Open champion, too, remained undefeated against Uzbekistan’s Denis Istomin, winning comfortably in straight sets, 6-1, 6-4, 6-2, to advance to the second round.

Fifth-seeded Milos Raonic too cruised into the second round with a straight-sets victory Dustin Brown. Raonic defeated Brown, 7-5, 6-3, 6-4, in one hour, 43 minutes. No. 10 Gael Monfils got the better of Gilles Muller 6-4, 6-2, 7-6, while ninth seed Jo-Wilfried Tsonga recorded straight sets 6-3, 6-4, 6-4 win over Guido Andreozzi to get his 2016 US Open campaign underway.

However, it was a thrilling five-setter between No. 26 seed Jack Sock and 18-year-old Taylor Fritz in which Sock beat Fritz, 7-6, 7-5, 3-6, 1-6, 6-4, in Louis Armstrong Stadium.

Meanwhile, veteran John Isner was stretched to five sets by teenager Frances Tiafoe at the new Grandstand but managed to hold off the challenge, turning back Tiafoe 3-6, 4-6, 7-6, 6-2, 7-6 in a nearly three and half hour duel.