When I took off my shoes in the locker room, I had blood all over my socks," Djokovic reflects on his rivalry with Nadal and the 2012 Australian Open final

Novak Djokovic got off to a perfect start at the US Open late Sunday into Monday, dominating Learner Tien (6-1, 7-6, 6-2).

The Serbian also took advantage of the days leading up to the tournament to record a podcast with Jay Shetty, in which he discusses many topics surrounding his legendary career.

His historic rivalry with Rafael Nadal was one of the topics, highlighting an unparalleled physical challenge:

"Rafa Nadal was my most physically demanding opponent. We played the longest Grand Slam final in history in Australia. 5 hours and 53 minutes, I believe. So, 6 hours of grueling battle.

I remember the ceremony after the match. We were listening to the sponsors' speeches and such, but at one point, we both leaned over. I could see his legs shaking, and mine were shaking too. Someone noticed us and brought us chairs and water, and we finished the ceremony like that.

I should mention that when I took off my shoes in the locker room, I had blood on my socks. I couldn't even walk.

I've had incredible battles against Nadal. On clay, the slowest surface, playing Nadal is one of the greatest challenges that has ever existed in our sport. He was on every ball, and I was also an excellent defender, always in great physical shape.

We pushed each other to our physical and mental limits. I take a lot of pride and satisfaction in having had this rivalry with him. We didn't just write the history of our sport, but we also improved each other. We brought so much emotion to the people who watched us.