Melbourne (AFP) - Germany's Alexander Zverev said a more relaxed approach had worked wonders at the Australian Open and helped him break a mental barrier to make his first Grand Slam semi-final.
The 22-year-old rallied from a set down to shatter the dreams of 2014 champion Stan Wawrinka 1-6, 6-3, 6-4, 6-2.
Big things have been tipped for Zverev since he burst into the top 10 in 2017, but until now he has not fully delivered at the Majors.
But after a poor build-up to the year's opening Major at the ATP Cup, where he lost all three matches, he worked hard on the practice court and changed his routine to take the pressure off.
"I mean, I've done well at other tournaments. I've won Masters Series, World Tour Finals. But the Grand Slams were always the week where I kind of even wanted it too much," he said.
"I was doing things in a way too professional way. I was not talking to anybody. I wasn't going out with friends. I wasn't having dinner. I was just really almost too focused."
"I changed that a little bit this week," he added.
"I'm doing much more things outside the court. I also was playing that bad at ATP Cup that I didn't have any expectations. I wasn't really expecting myself in the semi-finals or quarter-finals.
"Maybe this is a stepping stone. Maybe this is how it should happen."
He added that having his best friend, girlfriend and a close team around him also helped.
His reward is a clash against either Rafael Nadal or Austrian fifth seed Dominic Thiem in the last four, with a final beckoning against Novak Djokovic or Roger Federer.
"It feels awesome," said Zverev, who has been donating $10,000 for each win at Melbourne Park to Australian bushfire relief, and will even hand over the Aus$4.12 million ($2.78 million) winner's cheque if he clinches the title.
"I hope I can still continue to play better in the semi-finals and hopefully maybe in the final. The people that I'm going to play are not getting worse."
- Crunching groundstrokes -
Zverev's serve, a key focus of his extended practices, was a weapon once again against 34-year-old three-time Grand Slam champion Wawrinka.
He fired 13 aces against just one double fault, with a first-serve percentage of 80 percent.
It was Wawrinka who came out of the blocks firing, putting immediate pressure on the Zverev serve to break straight away when the German netted a half-volley.
Zverev won just four points in the opening three games as he struggled to get the measure of Wawrinka, and he was broken again when he shanked a forehand high into the crowd.
The German finally held to get himself on the scoreboard but the Swiss was moving and serving well, unleashing some crunching groundstrokes to take the set in just 24 minutes.
Zverev needed to hold his opening serve in the second set to halt the Wawrinka juggernaut and he rose to the occasion, with his court coverage and groundstrokes raising a level.
It went with serve until game eight when Wawrinka drilled a forehand into the net and Zverev screamed 'C'mon' after his first break of the match, serving out for the set.
A resurgent Zverev rammed home his advantage with an early break in the third set before the Swiss hit back. But a poorly executed drop shot again handed the 22-year-old another break and he raced to a two-sets-to-one lead.
Wawrinka was out of fight and Zverev had him dancing to his tune as he raced to victory.