WELLINGTON: The racket had it coming. It had been annoying him for some time and deserved it, according to Alexander Zverev.

So the 19-year-old German took matters into his own hands and smashed it twice into the Hisense Arena ground at the start of the fourth set in his Australian Open first round clash with Robin Haase on Tuesday.

It worked. The cathartic release ended a flurry of unforced errors and double faults flying off his racket and enabled him to fight back and advance to the second round with a 6-2 3-6 5-7 6-3 6-2 victory over the 29-year-old Dutchman.

"I think letting my frustration out in the beginning of the fourth helped me a little bit," Zverev told reporters. "Sometimes you just have to let go."

Prior to that outburst, Zverev, considered one of the best players among the 'Generation Next' of athletes on the men's circuit, had been facing the real possibility of an early exit after he lost the second and third sets and been broken early in the fourth.

He didn't like the thought of that.

"If you're down two sets to one and 2-love ... there are thoughts going through your head a little bit," he said. "But I kept playing, and I knew I had to keep playing and try my best.

"Obviously getting that first break back in the fourth set, I really felt like I could still do it. That's how it went then (and) I'm happy to get out of that."

The gangly Zverev, who made two finals last year and won the St. Petersburg title with victory over Stan Wawrinka, added he felt that he had Tuesday's match won when it entered the fifth set.

"I think the mental battle, if you can call it that, was more in the fourth set when I broke him back, and then I broke him right again to win the set," he said.

"I think he broke down a little bit then. He got a little bit tired, I thought. His energy went down.

"I don't know if that's because he's tired or if because he lost the fourth set where he may have thought he should have won. But I picked it up and I played great the fifth set."