German qualifier Daniel Altmaier, ranked at 186 in the world, stunned seventh seed Matteo Berrettini of Italy to reach the Roland Garros last 16 on Saturday with a hat-tip to Stan Wawrinka, Rocky and early morning Zoom calls.
The 22-year-old Altmaier triumphed 6-2, 7-6 (7/5), 6-4, becoming just the fourth man since 2000 to reach the round of 16 on his Grand Slam debut.
Victory also means an unexpected financial windfall for the German who is guaranteed to make at least $221 400 by reaching the last 16 having earned just $173 600 in his entire six-year professional career.
It's been a long, tough road for Altmaier who says three-time major winner Stan Wawrinka is his "great role model".
A succession of injuries to his back, shoulder as well as hip, caused by a freak slip on a tennis ball on a hard court which sidelined him for most of 2018, put his career, which had shown some promise with a quarter-final run at Antalya in 2017, on hold.
Just over 12 months ago, his ranking had slumped to 515.
For Altmaier, the help of Wawrinka has been invaluable and he paid tribute to the 2015 Roland Garros champion after the win on Saturday, pressing an index finger to his temple to mark the breakthrough in the style of the veteran Swiss star.
"He also helped me a lot when I was injured," said Altmaier who has an Ukrainian father, a Russian mother and has hit with Roger Federer.
"Having a friendly relationship with such a top player who has achieved an incredible amount in our sport is really something special."
He added Saturday: "When I was watching him, he always says 'Allez, Stan.' I copy him a little bit because I like to say, 'Allez, Dan'.
"He has been a huge reason why I'm healthy now."
'Even Rocky would collapse'
Altmaier has been working with noted coach Argentine coach Francisco Yunis for a year and worked hard on his fitness during training sessions. It has been tough but rewarding.
"If he had done our training programme, even Rocky would have collapsed," Altmaier told Eurosport of his brutal workouts under Yunis.
Even lockdown didn't save him from physical exertions.
"It's a funny story regarding how I got fit in the quarantine and coronavirus time. I was working via Zoom with my physical coach from Argentina," he said.
"We worked 11 weeks basically in a room, every day, five, six times a week. Sometimes he was waking up at 5 a.m. to give me my schedule, push me through my sessions."
Playing at a Grand Slam is a world away from the second-tier Challenger events that Altmaier usually contests.
Prior to the suspension of the tour in March, he took part in Challengers in Ann Arbour in the United States, Launceston in Australia, Bangkok and Morelos in Mexico.
On the eve of Roland Garros, he was injured at another second-tier event in Aix-En-Provence and needed the last-minute green light from the doctors in order to compete in Roland Garros qualifying.
"For me, personally, tennis is doing a big change at the moment. I was feeling this already on the Challenger tour, even Futures tour. Literally everyone can beat everyone at the moment," he said.
"Physically everybody is getting stronger. Tennis-wise players are playing smarter, they are more disciplined. You can see this by following the last Grand Slams. Especially here in Roland Garros, tennis has really changed after this corona break.
"I'm happy to be one of them who is showing his skills," added Altmaier who faces Pablo Carreno Busta, the Spanish 17th seed, for a place in the quarter-finals.