Record-extending meetingpublished at 08:03 Greenwich Mean Time 27 January 2019
Djokovic v Nadal
These two are no strangers. They have met in plenty of Grand Slam finals already - seven to be exact.
Add another five semi-finals, 17 Tour-level finals and an Olympic semi-final and it's fair to say these two have a strong rivalry.
Today's match will be an ATP record-extending 53rd meeting between them.
"It is the biggest rivalry we've seen in tennis history," Australian former Wimbledon champion Pat Cash said.
It is also the first time the two have met at the Australian Open since their epic five-set final in 2012, which Djokovic won with almost six hours on the clock.