Alexander Zverev has been training up to seven hours a day as the German desperately tries to work his way out of a form slump.

The German had a horror time of it during the ATP Cup, crashing to three disastrous losses as his serve deserted him.

Zverev, 22, says his preparations for the Australian Open had been way behind and he needed to do something drastic to catch up.

“I’ll probably spend more hours on court than anybody else this week,” he told reporters.

“I have been practising five, six, seven hours sometimes a day, which nobody really does a week before a grand slam.

“I need to get my tennis back because the way I was playing at the ATP Cup is not going to be good enough to do well at a grand slam.

“This was more like a training block for me than preparation for a grand slam.

“All we’ve been doing for the past few days is come here at 9.30am and leave at 9pm, 10pm sometimes.

“It’s something new, something different and maybe it will work for me.”

Zverev said some gruelling sessions working on his serve were already paying off.

“I’m also not player that gets too nervous or too emotionally down so when something doesn’t work at practice, that’s when it doesn’t work in matches,” he said.

“At the ATP I was not able to serve in practice as well.”

A player who has long been touted for great things, Zverev’s grand slam record is largely unimpressive.

His best performances have been quarter-finals at the past two French Opens, while last year’s fourth-round exit was his best performance at an Australian Open.

Zverev will face Italian world No.76 Marco Cecchinato in the first round at Melbourne Park on Tuesday.