“For me what upset me the most is not the third set, it’s the fifth set,” when he was serving for the championship at 5-3.

“I had a lot of chances in the fifth set and didn’t use them,” he added.

The second-seeded Thiem beat the fifth seed Zverev 2-6, 4-6, 6-4, 6-3, 7-6 (8-6) in four hours and two minutes.

It was the first time in the US Open’s Open-era history that a player had recovered from losing the opening two sets to win the title.

It was also the first time the final had been settled by a tiebreak.

Zverev said it hurt to lose in the manner he did.

“Obviously being two sets to love and a break up in a grand slam final then losing is not easy,” he told reporters.

Zverev’s debut appearance in the last-two of a tennis major came after he reached the semi-finals of the Australian Open earlier this year.

Zverev said the rawness of the Flushing Meadows defeat meant it was too soon to say whether he had taken any positives from going a step further.

“That question is probably two, three days too early to ask right now,” he said.

But the German, who came into the tournament ranked seventh in the world, added that he was sure he would capture a tennis major in the future.

“I’m 23 years old. I don’t think it’s my last chance. I do believe that I will be a grand slam champion at some point,” he said.