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Four days before claiming the biggest win over his career, Walton had been ready to purchase a ticket for a 5.08pm flight to Mexico City for an ATP Challenger Tour event in Morelia. 

He had been the fourth player on the lucky-loser list for the Miami Open and the second round of the main draw was underway.

Final-round qualifying losers Camilo Ugo Carabelli, Gabriel Diallo and Hugo Gaston had received a call-up and Walton was preparing to leave Miami for Mexico and the next stop on a nomadic journey through the Tour's challenger circuit.

“I had it all planned. I [had] all my stuff packed in the car, ready to go,” Walton told ATPTour.com. “If I lost, I was out of here.”

The Australian was on court warming up countryman Rinky Hijikata for his match when he received the news from an ATP tour manager that he would replace Hubert Hurkacz - the 21 seed - in the draw. Since Hurkacz was seeded, Walton would begin his tournament in the second round.

“Wins have been hard for me on the Tour," Walton said. "I think this was win number five out of 20-something, so I haven't won that much on Tour. 

"I've done well at the Challenger level. Playing these big tournaments is obviously very rewarding, especially if you can win matches, because they offer the biggest prize money, and just everything around the big tournaments.”

Walton's wild ride continued with a gritty win over Hong Kong 20 year-old talent Wong, the Australian setting up a clash with local hope Fritz.

“You're seeing the big guys, the big names in the locker room. It's pretty cool,” Walton said. “You don't take it for granted, and you just try your best, and there's so many people chasing to be at these tournaments, so you don't take playing these for granted. Everyone earned their spot here.

“I'll just do my best to give it everything.”