Kohli took to Twitter and wrote, "And congratulations to @nagalsumit for qualifying for the #USOpen. A humongous task facing the great @rogerfederer, but we will be cheering for you. Best Wishes and Goodluck."
The 25-year old Nagpal qualified for the US Open main draw on August 23 and become the youngest Indian to qualify for the main as he defeated Brazil's Jaao Menezes 5-7, 6-4, 6-3.
This will be Nagal's first appearance in a Grand Slam tournament. He had earlier won the Wimbledon Boys' doubles title in 2015.
Nagal will be the second Indian to take part in the US Open 2019 men's singles event. Prajnesh Gunneswaran had earlier qualified for the tournament as he gained automatic qualification.
This is the first time since 1998 that two Indians will be participating in the men's singles event of a Grand Slam.
In 1998 Wimbledon tournament, Leander Paes and Mahesh Bhupathi had represented India in the singles event.
Gunneswaran will take on Daniil Medvedev in the first round match on Monday, August 26 while Nagal will face Switzerland's Roger Federer in the first round match on August 27.