Dominic Thiem comes from two sets down to beat Alexander Zverev in US Open final

For the first time the US Open was settled by a fifth-set tie-break, with Thiem, who joins Thomas Muster as the only Austrian to win a slam title, proving just a bit stronger in the end.

Ever since Novak Djokovic's disqualification ensured the first new men's slam champion for six years, the question had been which of the young contenders would seize his chance.

Thiem is closer to 30 than 20 but has certainly paid his dues with losses in his first three slam finals, twice to Rafael Nadal at the French Open and to Novak Djokovic at the Australian Open in January.

He had played this fortnight as if he believed this was his time but, when the final came, it was immediately clear who was carrying the weight of expectation on his shoulders and in his legs.

Zverev had struggled through the tournament, playing two horrific sets against Pablo Carreno Busta in the semi-finals before choosing the perfect moment to come back from two sets down to win a match for the first time.

That sent him through to his first grand slam final and the contrast could not have been greater as he played with a looseness in his arm that immediately had Thiem on the back foot.

This was the Zverev who put tennis on alert that another young superstar was emerging and who has gone AWOL at the slams far too frequently.

His forehand, sometimes a liability, was forceful and penetrating, his serve the weapon it should be but so often is not, and his head clear and focused.

He smothered the court, pushing forward to the net at every opportunity, while Thiem was so far behind the baseline he was in danger of colliding with the line judges.

The Austrian needed treatment to a right Achilles problem during his semi-final victory over Daniil Medvedev and his fitness was one of the big question marks going into the final.

There were no obvious signs of hindrance but this was not the Thiem who reached the final for the loss of just one set.

He made a slew of unforced errors and found himself staring at humiliation facing set points at 1-5 in the second set.

To his credit, he dug in, and a a simple volley placed wide on set point from Zverev hinted at a turnaround, with Thiem winning three games in a row.

But the German made sure his minor wobble was nothing more than that by serving it out at the second opportunity, sealing the set with an ace.

When he broke serve again to lead 2-1 in the third set, the trophy was within touching distance, but somehow the feeling remained that it was far from finished.

Partly that was due to Zverev's ongoing second serve issues, and the double faults racked up as Thiem gradually dragged him into a dogfight.

The second seed got his reward when a poor service game from Zverev cost him the third set, and suddenly the match had a different complexion.

A break in the eighth game of the fourth set was all Thiem needed to send the contest to a decider.

The script seemed written when Thiem broke to start the decider but it was ripped up several times before the final shot was hit.

Zverev broke back straight away, took advantage of a physically-ailing opponent to move to 5-3 only to play a nervy game serving for it.

Back came Thiem with three games in a row but, after calling the trainer for a thigh massage, he could not serve it out either.

Thiem could barely walk but he could still compete. He set up two match points only to miss makeable forehands on each of them.

But on the third chance, Zverev went wide and Thiem slumped to the court in celebration and exhaustion before sharing an emotional hug with his vanquished opponent.