Novak Djokovic didn't play in last year's US Open because of injury and Juan Martin del Potro nearly quit the sport three years ago, also over frustrations caused by injuries.
Now they are set to face each other on Sunday for the first time in a grand slam final on the biggest stage in tennis, the US Open in New York.
Djokovic, ranked sixth in the world, cruised through earlier rounds of the tournament, dropping only two sets and being pushed to a tiebreak only once.
He'll be looking to continue his momentum after winning Wimbledon in July and the Western & Southern Open in August.
It would be his third US Open title and would bring his total grand slam haul up to 14, a sweet achievement after suffering an elbow injury last year that forced him to take about six months off.
"I was fortunate not to be too long away, but I did carry my injury for over two years, so I understand what a player goes through," the 31-year-old Serb said.
Djokovic's record compares with one grand slam for del Potro - the US Open in 2009. That might make him the hungrier player but a large contingent of Argentines is sure to make him the crowd favourite.
Del Potro, who turns 30 later this month, reached the final unexpectedly when world No.1 Rafael Nadal pulled out two sets down in the semi-final on Friday.
"It will be special to me. A big challenge because I've been fighting with many, many problems to get to this moment," he said.
Del Potro's career hit bottom three years ago due to wrist injuries that required multiple surgeries.
"The worst moment was in 2015 when I was close to [quitting] this sport because I couldn't find a way to fix my wrist problems," he said after the match with Nadal. "I was suffering a lot. I got depressed for a couple of months also."
But he said he trusted his surgeons and has now put that "completely in the past." He's risen to No.3 in the world and all his hard work would pay off nicely with a defeat of Djokovic. He's done it before, but only four times in 18 meetings.
Through all those matches and their years on the tour, the two players said they have become friends, which will make playing the final more difficult.
"He's a dear friend, someone I respect a lot," Djokovic said on Friday after beating Kei Nishikori in his semi-final.
Djokovic, who is 10 centimetres shorter, said del Potro can rise to the occasion of a big match and he is especially wary of his opponent's forehand and big serve.
Del Potro also acknowledged their close friendship and noted that his opponent won Wimbledon, the most recent grand slam.
"He's playing so good. He will be the favourite to win on Sunday," he said.
But del Potro might have an ace up his sleeve - a group of 14 mates who have come to New York from his home town of Tandil, Argentina.
They have been at all his matches over the course of the fortnight and their constant chanting is inspiring him.
Del Potro has acknowledged their presence, joking about their consumption of beer but he said he draws energy from them.
"They are very important for me to be on this stage at the moment because they were behind me in ... trying to keep my mind ... positive," he said
"I didn't know if I will be a tennis player again or not. But I'm here. I'm excited to keep surprising the tennis world as I did myself."
