Frances Tiafoe digs deep in gutsy US Open win over Aleksandar Kovacevic

Frances Tiafoe got a test in his U.S. Open opener.

And he passed it.

Pushed by New York native Aleksandar Kovacevic, Tiafoe had to gut his way to a 6-4, 6-3, 4-6, 6-4 first-round victory at Louis Armstrong Stadium.

“It got pretty tough there at the end,” Tiafoe acknowledged in an on-court TV interview. “When they closed the roof, it got really muggy there. I was really struggling breathing. In the middle of the fourth it got better.”

The naturally ventilated roof closed to deal with brief rains out in Flushing Meadows, and Tiafoe struggled with both the steam conditions and the hot play of his Manhattan-native foe.

Kovacevic was making his U.S. Open debut in his home Grand Slam, and was up to the challenge.

But Tiafoe came through in the end.

Back in the top 20, Tiafoe did a good job of keeping his composure.

He’s vowed to win the U.S. Open and is the first American to reach at least the quarterfinals in back-to-back years since Andy Roddick.

This was a tough first step in trying to make it at least three straight quarters.

Tiafoe took advantage when Kovacevic gave him the slightest opening in the 10th game of the first set, the Prince George’s County (Md.) native elevating and drilling an overhead to win the first set.

Then Tiafoe took the second set when Kovacevic sailed a backhand long.

The third set saw Kovacevic find his footing.

He hit an awesome forehand winner right on the line in the fourth game, raising the roof and bringing the crowd to its feet.

But Tiafoe broke to go up 6-5 in the fourth, and after failing to convert his first four match points, the fifth time was the charm.

When he plopped down in his chair, leaned back and put his towel over his face, it was more relief than celebration.

Tiafoe has been up and down this year but made the final of the Cincinnati Open last week to break back into the top 20.

Next up in the second-round of his 10th U.S. Open he faces Alexander Shevchenko of Kazakhstan.

“I’ve been around for [awhile]. That 10 years goes really fast. Hope to be around another 10,” Tiafoe said. “I just remember a little kid with a lot of dreams.”

It was a good showing for Kovacevic, the son of immigrants.

His mother Milanka is from Bosnia and Herzegovina, and his father Milan Kovacevic — who worked at Columbia University — is from Belgrade, Serbia.

Kovacevic grew up on the Upper West Side and started playing at age five at Central Park Tennis Center.

He attended Booker T. Washington Middle School and Beacon High School, where he was relegated to third doubles as a freshman.

But he trained all over the city, in Harlem and at the USTA Billie Jean King National Tennis Centre.

At 11, he attended an open tryout for the John McEnroe Tennis Academy and was chosen by McEnroe among a group of 200 students to get a full scholarship.

Now he’s playing at the U.S. Open, and walked off to an ovation from the crowd celebrating a native son.