Melbourne: Stan Wawrinka delights in the fact that his favourite nickname, 'Stanimal', was given to him by Roger Federer, who he also admits is simply the greatest player to have picked up a tennis racquet.
Together the Swiss duo teamed up to win an Olympic doubles gold medal at Beijing in 2008 and the country's first and only Davis Cup triumph six years later.
On Thursday, however, their friendship will take a back seat when they walk out on Rod Laver Arena for an Australian Open semifinal that promises to be one of the highlights of the season-opening Grand Slam.
It will be the 22nd time the pair have met and Federer, back after six months out and shortening as the bookmaker's favourite to capture his fifth Australian Open crown, has won 18 of the head-to-head match-ups.
He has also looked to be back to his best in beating 10th seed Tomas Berdych, fifth seed Kei Nishikori and then destroying Mischa Zverev, who had upended world number one Andy Murray, in the quarter-finals.
While Wawrinka was won just three of their clashes, the 35-year-old Federer places no such stock in that statistic. All that matters is how his opponent pitches up in their next match.
And with someone like Wawrinka, the 17-times Grand Slam winner knows how much his 31-year-old compatriot has progressed since their first meeting indoors in Rotterdam in 2005.
Back then Wawrinka, he said, struggled with the faster surfaces. His footwork was not there. You could tell from the other side of the net that he did not enjoy playing on grass or hard courts.
So the younger Swiss did what anyone would do. He sought advice and Federer became a counsellor of sorts.
Gradually, as the calls became less frequent, Federer realised that Wawrinka had 'got it'.
"What I like with Stan is if I would tell him something, I felt like he was able to do it," Federer said. "That showed me that he's a great player, that he's got a mind of somebody who understands what I'm trying to explain to him."
Federer said the mentoring had stopped well before Wawrinka won his maiden Grand Slam at the Australian Open in 2014, though the fact he did it at Melbourne Park was a surprise given his early struggles on hard courts.
"If I would have called any Grand Slam for him to win it was always going to be the French, because he moved so effortless on clay. That's his base. That's his DNA really," Federer added.
"I think he's done incredibly well on all the other surfaces, including grass actually, also indoors, hard and fast.
"He's become such a good player, I super respect that, that the guy is able to transform his game around like that, in his footwork, in his mind, also in his game plan.
"That's his transformation, and I like what I saw."
Wawrinka's transformation now includes two more Grand Slam titles, including last year's U.S. Open, and while he typically has a downbeat approach to his matches, the world number four is confident he has the game to beat Federer.
"I'm more confident with myself. When I step on the court, doesn't matter who I play, I know what I have to do if I want to win," said Wawrinka, who was taken to five sets by Martin Klizan in the first round but has improved with each ensuing match.
"Against Roger, it's always special because he's so good. He's the best player of all time. He has answers for everything.
"But I managed to beat him in a Grand Slam, so we'll see."
Only three women can now prevent Serena Williams from clinching a 23rd Grand Slam title on Saturday, her sister Venus, a younger compatriot and a 34-year-old Croatian she last played nearly two decades ago.
The quartet take to Rod Laver Arena on Thursday with Serena playing Mirjana Lucic-Baroni and Venus facing Coco Vandeweghe at the business end of an Australian Open where upsets have been a daily occurrence.
The seedings have not proved much of a guide in the women's draw this year, with world number two Serena the sole survivor of the top 12 at the start the tournament.
The head-to-head will not provide much help either when assessing Serena's matchup against Lucic-Baroni, given their last meeting came in 1998 at Wimbledon when they were both 16. "It was on Centre Court. That's all I remember. I remember winning. I was so excited because I was so young. She obviously was super young, too. That's all," Serena said on Wednesday after beating Johanna Konta in the quarter-finals. "We have totally different games now, the both of us. We both have gone through a lot. We both have survived, and here we are, which I think is a really remarkable story."
As six-times Melbourne Park champion, Serena will be clear favourite, of course, more so because she has reached her 34th Grand Slam semifinal without losing a set.
Lucic-Baroni's path to the last four has been more of a battle, as befits a woman who has overcome huge adversity to get back to the top of the game after years in the wilderness.
While Serena missed the back end last season with a shoulder problem, Lucic-Baroni has more immediate concerns about an injury to her left leg.
"I'm going to be just fine," said the world number 79. "I'm going to recover, do some therapy, and I'll be fine. I'll just put some extra tapes on and hopefully it will hold me together. I'll fight hard. I'll be okay."
The first semifinal is an all-American affair pitching Venus, the oldest woman in the draw, against 25-year-old surprise package Vandeweghe.
Venus does not have an Australian Open crown in her collection of seven Grand Slam titles and has reached the final just once, losing to Serena in 2003.
Vandeweghe has got to the last four of a Grand Slam for the first time here by blowing opponents off the court with her booming serve and big winners.
Venus might be hoping that the occasion gets the better of the world number 35 but promised nevertheless that the power tennis would not be coming from just one side of the net.
"Power is her game, her strength. She's putting the ball in with it, it's awesome to see really," Venus said.
"(But) I play a power game as well. I've been fortunate enough to play good defense and have good movement around the court. Hopefully this will be a plus for me."
Vandeweghe was seven years old when Venus first played at the Australian Open and said it remarkable to think she was about to face a player she once asked for an autograph.
"It's a dream to play someone you grew up watching," she said. "To play an unbelievable player, future Hall of Famer, Venus, to be on the court with her but to do it at this stage of a Grand Slam is kind of crazy."