Darren Cahill, the coach of the Wimbledon champion, has spoken of the close bond the pair have, as well as the improvements he has seen in her tennis.

MELBOURNE, Australia – When Simona Halep takes to the court in the quarterfinals of the Australian Open on Wednesday, she will do so with long-time coach Darren Cahill back in her box.

Over the course of 2019, the pair were officially on a break from working together on a full-time basis, though the Australian coach admits that he missed collaborating with the Romanian – a person he considers part of his “family” – too much to take a back seat entirely.

READ MORE: Halep holds off Mertens to return to Australian Open quarterfinals

Indeed, Cahill says that aside from his physical location by the side of the WTA World No.3, not much has changed.

“We would speak most days, even last year when we weren't working together,” he revealed. “We're friends. As I have said many times before, she's really a part of my family.

“I told that story about thinking I was doing the right thing for my family over 12 months ago when I came home and said, ‘Hey, kids, I'm taking a year off work and I'm going to be around a little bit more,’ and my daughter started crying. I thought she was really happy, but she was annoyed that I was leaving Simona. That's what she means to my family.

“So not much changed. I just wasn't at as many tournaments, obviously. I spoke to her most days at Wimbledon last year, spoke to her most days during the US hard court season, and we started working a little bit together before Shenzhen.

“As far as I'm concerned, the relationship is exactly the same. She's still as stressed on the court as she always is, but she's learning ways to deal with it and to handle it.”

Photo by Getty Images

Ahead of her quarterfinal against Anett Kontaveit, Cahill believes that he has seen evidence of a new-found maturity in his charge’s game over the course of the tournament, citing an example from her straight-sets last-16 victory over Elise Mertens.

“After letting two breaks slip and then having chances in the 4-3 game in the second set, Simona got back to 4-all, had break points in the 4-all game and missed them. The old Simona would have let that game go, but she refused to give up in that game,” he said.

“That's what I'm most proud of is that fight that she's showing when a few things go against her. That's been the big change in her I have seen over the last two or three years.”

LOOK: The fourth round of the Australian Open in pictures

Artemon Apostu-Efremov, who is working with the Halep camp, agreed that mentally she has become a far superior player in the years he has known her from back in Romania.

“Obviously she improved her game, but I think for her the biggest improvement was when she was around 60 in the world, she changed her attitude towards the game, and she understood better the concept of the game. She let the matches that she lost go away and focused on the next match,” he explained.

“This was a big change. It's a process that goes on and on. For sure, having Grand Slams under your belt helps a lot, because these are the confirmations that you need that you're on the right track, but I think in order to be a very good player, you have to evolve as a person inside and outside the court.”

2020 Australian Open press conference: Cahill ‘That’s what I’m most proud of, the fight that Simona is showing’

Cahill, meanwhile, was full of praise for the efforts of compatriot Ashleigh Barty, who rose to WTA World No.1 in 2019, a year in which she also sealed her first major title at Roland-Garros.

“Everything that Ash has done in the last two or three years has been inspiring for all of us. And it's not just what she's been able to do between the lines. It's the way she's been able to do it and the way she's conducted herself outside of the lines,” he said of a potential final opponent for Halep.

“She's an inspiration for not only the young generation here in Australia but for everybody. My generation, as well. She epitomizes what we think Australians are all about. And that is hard work, give it your best shot, being really humble in success, and shaking somebody's hand if they are too good for you and saying: ‘Well played, mate. You were too good today.’

“That is Ash Barty. I think that sums her up. The fact that she won the Young Australian of the Year Award at the honours, Australia Day Honours, she thoroughly deserves that because she is genuinely a great person.

“I'm really happy for her. If we are lucky enough, Arte and I, to be coaching against her on Saturday, that would be a good problem to have.”

Photo by Getty

Cahill will be back in Halep’s corner on Wednesday as she attempts to reach her second Australian Open semifinal in three years against an opponent she has beaten in both their previous meetings.

"Simona will be as nervous in the next match as she was before the last round," added Cahill. "The great thing about the WTA at the moment is there are so many great story lines coming through from different nationalities, from different types of players. It's in a pretty healthy situation at the moment, and the matches have been great. We keep our fingers crossed and hope they continue to be."