Alexander Zverev has said that he is 'back' after defeating Jannik Sinner in a five-set battle to reach the US Open quarter-finals.

The twelfth seed has been solid throughout the last Grand Slam of the year at Flushing Meadows, ousting Aleksandar Vukic, compatriot Daniel Altmaier, and nineteenth seed Grigor Dimitrov before his Round-of-16 clash with sixth seed Sinner.

Moreover, the German player entered the Slam off the back of a successful time on the North American swing, reaching the semi-finals of the Cincinnati Open before being defeated by eventual champion Novak Djokovic.

The 26-year-old has been ranked as high as World No. 2 in the ATP Ranking, and was continuously in the top 10 from July 2017 until November last year. However, he sustained an ankle injury at the 2022 Roland Garros that tore all three lateral ligaments.

Therefore, it took him a while to recover and he subsequently dropped in form and in the rankings, but it now seems as though he's making his way back toward the top.

He demonstrated great endurance in his battle with Sinner, which lasted a grueling four hours and 41 minutes, the longest match of Zverev's career. Although it was close, he ultimately had the edge, winning the match 6-4, 3-6, 6-2, 4-6, 6-3.

Speaking after the match, Zverev expressed his joy at being back on form.

"Longest match ever! Well, I guess I can say I am back, right? So, it’s a..I don’t know, this is what I live for, this is what I absolutely love to do.

"I would have loved to play a little bit shorter, that’s for sure but you know last year when I wasn’t able to play, this is exactly the moment that I missed, playing until 1:30 am in front of a packed crowd in Arthur Ashe Stadium. There is nothing better."