At five hours and 14 minutes, that battle seven years ago was then the longest match in the tournament’s history with a shattered Nadal showing incredible resilience to win 6-7 (4/7), 6-4, 7-6 (7/2), 6-7 (1/7), 6-4.
Despite the brutal but high-quality marathon, he went on to spend another four hours and 23 minutes on court to beat Roger Federer in the final and win his only Australian Open title.
The two Spaniards have been pitted together again at Melbourne Park and despite Verdasco slipping down the rankings to 47, Nadal knows he has his work cut out.
“Very tough first round. Not a lucky first round, I think, for me. For him either,” said Nadal, seeded five.
“Will be a tough match. I need to be ready to play very good tennis if I want to be through.”
Nadal, who lost to Novak Djokovic in the Qatar Open this month, still has vivid memories of the 2009 encounter with his fellow left-hander.
“Obviously that match gave me the chance to win the only Australian Open that I won. That was an unforgettable memory for me. I think it was a huge level of tennis there. Some spectacular points,” he said.
“A lot of people always talk to me about that match. I enjoyed that match. Was a tough one. Was a great experience.”
Asked if it was more difficult playing a fellow left-hander, Nadal, 29, said it was not important.
“I played a lot of times with lefties. We’ll see. But it’s not about playing against a lefty, is about playing against a player that has a huge potential, is able to reach a great level of tennis,” he said.
“If you are not playing your best, it is a very, very dangerous match.”
Nadal endured his worst season in a decade last year and is looking for a solid start to 2016.
The former world number one’s reign as French Open king ended at the quarter-final stage in 2015, and he also failed to reach the semi-final of the US Open, Australian Open and Wimbledon.
If he gets past Verdasco, his next major challenge should come against Swiss fourth seed Stan Wawrinka in the quarter-finals.