Craig Kardon coached Martina Navratilova to the 1990 Wimbledon title, led Lindsay Davenport into the top 10 for the first time and drove Mary Pierce to No 5 in the world.

Now he's working with Coco Vandeweghe, guiding her into her first ever Grand Slam semifinal at the Australian Open. And the American is glad to have him in her corner.

After upsetting seventh seed Garbine Muguruza at Melbourne Park on Tuesday, Vandeweghe credited Kardon for helping her deal with the pressure-cooker atmosphere at the year's first Grand Slam.

"Craig and I get along great. It's definitely kind of a give-and-take relationship, where I take from him right now more than he's giving me," she said following her 6-4, 6-0 win that sets up a semifinal against Venus Williams.

"Before the match I was quite honest with him that I was a little bit nervous and I was a little bit scared.

"He's like, 'That's normal to feel like that. But go out there, you'll settle down in the warm-up. If it's not the warm-up, the very first game you'll be settled. Don't even worry about it'.

"It's just the calming voice of someone you trust, you know that trusts and believes in you, was enough for me to feel better about myself just in this one situation. That happens a lot."

The pair have been collaborating for several years and Vandeweghe extolled the virtues of having a patient and trusted coach, particularly for young players.

"I think it's very important for young players to get a good coach, it's what they need," she said.

"Maybe it's a leadership role, technical role, or a friendship role, something like that. Whatever it is, I think it's very important."

As part of Vandeweghe's preparations for Melbourne, Kardon, who has also mentored Jennifer Capriati, Ana Ivanovic, and Zina Garrison, insisted she play doubles.

The American, 25, who teamed up with Martina Hingis but was knocked out in round two, said it was all part of the grand plan to take her game to the next level.

"Absolutely. It gives me a better idea of where to be on the court as far as angles go," Vandeweghe said of the benefits of playing doubles.