"Everyone has a plan," Mike Tyson once said, "until they get punched in the mouth." You can adapt that to tennis, and to a young woman who won last year's French Open title with a brutal, ultra-aggressive game that roughed up all the rest on the Parisian dirt: "Everyone has a plan until Jelena Ostapenko starts firing forehands past you." 

Then your afternoon suddenly goes from the upright to the horizontal - splat into the baseline dust. Perhaps it was inevitable that Ostapenko, with her attacking mindset, would be drawn to swinging her fists as well as her racket. To prepare for the defence of her title at Roland Garros, the Latvian has turned to boxing to improve her cardiovascular fitness. 

On and off court, she's now in Fight Club-mode. And Ostapenko's interest in the sport would only have grown after she was introduced to Tyson during the recent Indian Wells tournament in California. If plenty of last year's chat in Paris was about her ballroom dancing - and she still goes once or twice a week when she's home in Latvia, including dancing the samba, the rumba and the cha cha cha - then expect the conversation this spring to touch on the pugilism. 

"I started the boxing a couple of months ago and I've done around seven sessions now. It's very good for your cardio in general," Ostapenko told wtatennis.com. "It's very useful for tennis players. I've heard that other tennis players are also doing it for their fitness programmes. I'm doing it with a coach, putting on the gloves and hitting the pads. I'm not [sparring] in the ring with anyone." 

Mike Tyson meets Jelena Ostapenko at Indian Wells

When Ostapenko's back in Latvia, she is constantly reminded of her improbable run to La Coupe Suzanne Lenglen last spring, when she was 20 years old, unseeded and, outside of tennis circles, pretty much unheard of.

"There's a tennis club in Riga which is named after me. Every time I go there, I see the stand they have built that's like the French Open and there's my trophy in the glass. There's also a TV that's always playing the final. Every time I go to practise there, it reminds me that I won the French Open because it's always on the screen." 

Not that Ostapenko really needs that footage on a loop to bring back memories of what happened in Paris; she also has the highlight reel that is regularly playing in the cinema in her head.

"One of my best memories from that fortnight was when I walked out into the stadium for the final and saw that all my family and friends were there. There were so many people who came from Latvia for me, just for the final - there were around 50 people. That was amazing. So when I saw all of them as I walked out, that was a great feeling," she recalled. 

"I'll also never forget what happened on match point when I hit the backhand down the line and dropped my racket. I was so happy that I won it. Another favourite moment was of course when I lifted the trophy as it was always my dream to win a Grand Slam and my dream had come true. I had always thought that I could win a Grand Slam but I hadn't expected it to happen at such an early age."  

French Open champion Jelena Ostapenko (Getty)

At any age, becoming a Grand Slam champion changes your life, on and off the court.

"The biggest difference now is that every girl wants to beat me. When they're playing me, that gives other players more motivation. I think players of my age, around 20 years old, are even more motivated now after I won the French Open," Ostapenko said. "Off the court, there's more attention and I have to do more things. In general, there are changes in how the tournaments and the people treat you. I'm spending more time doing media interviews and other appearances But that's OK. I enjoy it. It's a lot of fun. It's part of being a tennis player."

Some champions fret and fuss about returning to the place where they won their first Slam. But it sounds as though Ostapenko is avoiding that angst ahead of going back to Roland Garros.

"I don't think I'll feel any extra nerves when I go back to Paris as this year I've started as a Top 10 player. There was a lot of pressure at the beginning of the year but then I made the final in Miami and after winning some good matches on clay, I'm feeling much more confident. When I go to Paris, I'm just going to enjoy the fact that I've already won a Grand Slam at a very young age. That's what I want to do: to enjoy every match and to enjoy my tennis career."