PARIS (Reuters) - It is fair to say that Novak Djokovic and Ernests Gulbis have long held different approaches on how to become a top tennis player, yet the Serbian world number two and the reformed Latvian playboy will meet in the semi-finals of the French Open.
Gulbis lived on junk food and partied through the night, Djokovic, meanwhile, adopted a gluten-free diet and took training seriously.
So what do they have in common? They both attended the Niki Pilic tennis academy in Germany.
"Should I say what I remember of him?" six-times grand slam champion Djokovic said with a smile after beating Canadian Milos Raonic in the quarter-finals of Roland Garros on Tuesday.
"He was always somebody who was very enthusiastic about everything in life, and you could see he wanted to enjoy it with open arms."
Gulbis, who knocked out Roger Federer in the last 16 in Paris before reaching the last four with a comfortable win over Tomas Berdych, said Djokovic was already behaving like a champion as a teenager.
"He was really professional already at that time. I remember we had a friend, a Croatian guy who was all about the girls at that age already," he recalled.
"He was dressing up. He was looking good, putting perfume, sunglasses, going to talk to the girls. I see Novak, he's going to stretch."
Hernan Gumy, who knows a thing or two about dealing with party-loving characters having coached Marat Safin, tried his luck with Gulbis.
"First time when Hernan Gumy came to Latvia to prepare for Davis Cup. (Out of) eight days of preparation, I missed five days of practice," said Gulbis, who has yet to fulfil the promise he showed when he first burst into the limelight by reaching the Roland Garros quarter-finals in 2008.
He admitted last week that he was on a "last-chance train" to salvage his career, although it is not money or fame he is after.
"What is important for me to be truly happy. My happiness comes only from doing my job well," said the 25-year-old, who comes from a wealthy background.
"It's just about my inner comfort. That's it. For me, that's all that matters at the end of the day."
To achieve that, he may have to remember Djokovic's advice.
"Novak told me that you can have all the girls in the world... but to be really successful in tennis, you need to.... Something like that he said to me," he said.
Djokovic later said: "Talent is a gift... but it's a small part of a puzzle. Everything needs to come together to be a successful player."
So Gulbis made an effort - albeit rather belated.
"What took me so long? I think I was eating wrong. I had the wrong diet," he said with a laugh.
"Everybody was talking about this gluten‑free diet. My diet is full‑on gluten. I like a lot of ketchup, a lot of unhealthy stuff so there is a balance which I found in the last couple of years."
Gulbis has been coached by Austrian Gunther Bresnik for about two years.
"I missed a practice once with Gunther because I had a long night. I called him (at) 7:00 in the morning, and I said, Gun, I cannot come to practice. He understood it. It was once," he said.
It may happen a second time, though, as Gulbis promised he would "go big" to celebrate his victory over Berdych.
Reporting by Julien Pretot, editing by Pritha Sarkar