It's the ultimate David versus Goliath battle: world No.114 Aslan Karatsev up against the top-ranked titleholder Novak Djokovic in the Australian Open semi-finals.
A Russian qualifier on his grand slam debut against a 17-times major winner.
Karatsev's minimum Open pay day of $850,000 for a semi-final defeat would more than double his career on-court earnings of $798,700.
Yet that's still only about what Djokovic banks every week, with the Serb already tennis's biggest prize money winner after pocketing $188 million from his 81 professional titles.
Karatsev has played but 18 professional matches, Djokovic 1133 - 88 of those at the Australian Open alone.
Djokovic is challenging Roger Federer and Rafael Nadal as tennis's so-called GOAT - greatest off all time.
Karatsev has spent a decade toiling away in low-level Challenger and Futures events, winning only one of the 93 tournaments he contested before COVID-19.
Djokovic is unbeaten in eight previous Melbourne Park semi-finals.
But there is this for the Russian underdog: Karatsev has never lost in the main draw at Melbourne Park.
Such has been his incredible rise from tennis obscurity that, ranked 293rd in the world, Karatsev didn't even make the Melbourne qualifying draw last year.
He'd never beaten a top-40 opponent before this week.
Next week he could be in the top 40 himself after claiming the scalps of world No.9 Diego Schwartzman and two other members of the top 20 en route to the unlikeliest of places in the final four.
"I try to believe in what I'm doing on the court, and it's helped me to win matches," Karatsev said.
"I arrive to the court and say, 'I try to do my best with more belief'.'
"The key is the right coach that I found. I was really lucky to find him."
Karatsev, though, will need much more than Yahor Yatsyk's input to stop Djokovic.
Unbeaten in 27 matches in Australia since 2018, the Serb is on a mission to close the gap on Federer and Nadal on the men's all-time grand slam title leaderboard.
Djokovic has 17 slams, three shy of his two great rivals, and is refusing to let an abdominal strain slow his chase.
"I have not ever experienced that, to be honest, and I have never experienced this kind of injury during a grand slam and kind of keep going," Djokovic said.
"I have had a rollercoaster of a tournament since the third third round and an injury that happened, and unpredictability of what happens next.
"He doesn't have anything to lose, really. He's motivated. I expect him to come out and really go for his shots and try his best and try to take that win."
