Alexander Zverev riding a wave of confidence as he eases past Jannik Sinner at the US Open

Alexander Zverev in action

Fourth seed Alexander Zverev extended his winning streak to 15 matches with a straight-sets victory over Jannik Sinner to reach the quarter-finals of the US Open.

At 20, Sinner has been usurped as the young gun of men’s tennis by Carlos Alcaraz but great things are expected of the Italian and he tested Zverev without being able to take his chances.

Sinner fought back from a break down in the third set and held set point in the tie-break only to miss a routine forehand, and he paid a heavy price, with Zverev triumphing 6-4, 6-4, 7-6 (9-7).

The German is riding a wave of confidence, and he said: “I think definitely it’s the reason why maybe the big shots in the important moments they seem more natural, I would say, and you’re not maybe thinking about it twice like you would in some other situations.

“I’m happy where I am, I’m happy with how things are, and I’m happy with how things were the last few months. I’m in the quarter-finals now and from here on, the matches will definitely not get easier.”

Zverev has faced public allegations of domestic violence from an ex-girlfriend – which he denies – as well as a legal battle with his former agent over the past year.

He cited changes in his off-court life as a major influence in his success on it, saying: “The most important decision in my life was I think taking control of my own life.

Lloyd Harris celebrates

Lloyd Harris, pictured, celebrates victory over Reilly Opelka (Elise Amendola/AP)

“That’s what I have done at the beginning of this year. I’m taking control over everything – of my life, of my home in Monaco, of my business life, of my management, of companies that I want to work with.

“Everything is happening and going through me, which before everything was happening with the people I hired, which is a big difference. I feel like that shows on court, because that also does give you confidence. If you are in control of your own life, you are in control of your tennis.”

In the next round, Zverev will take on one of the tournament’s many surprise packages in South African Lloyd Harris, who reached a first Grand Slam quarter-final with a 6-7 (6-8), 6-4, 6-1, 6-3 victory over 22nd seed Reilly Opelka.