Novak Djokovic won his first match at the U.S. Open Tuesday night, keeping alive his quest to win the calendar Grand Slam.
Djokovic beat 145th ranked Holger Vitus Nodskov Rune in four sets.
Djokovic, the 2021 Australian Open, French Open, and Wimbledon Champion, dropped the second set to Rune.
However, he capitalized on his opponent's apparent injury. Rune struggled to run balls down in the third and fourth sets.
In the second round, Djokovic will take on another player ranked outside the top 100. Tallon Griekspoor won his first-round match for the opportunity to take on Djokovic.
The Serbian is six matches away from winning the calendar Grand Slam, which has not been achieved in men's tennis since 1969.