#3 Become the 1st player in the Open Era to win the double career Grand Slam
If Nadal triumphs at the 2020 Australian Open, it would make him the first player in the Open Era to win multiple titles at each of the 4 Grand Slam tournaments on the tennis calendar.
Only 5 players - Rod Laver, Andre Agassi, Roger Federer, Nadal himself and Novak Djokovic have won the career Grand Slam, the feat of winning all 4 Grand Slam tournaments during the course of one's career. If the amateur era (pre-1968) is included, Don Budge, Fred Perry, and Roy Emerson have also accomplished the career Grand Slam.
Emerson and Laver have achieved the double career Grand Slam but Emerson did so both times before tennis turned professional, and the first time Laver did so was in the pre-Open Era. Hence, Nadal's 2020 Australian Open triumph would create an unprecedented record in the Open Era.
You may also like: 3 milestones awaiting Nadal in 2020
What is the foot injury that has troubled Rafael Nadal over the years? Check here