It's been done before for sure, but maybe it needs to be done again, just check if Michael Phelps is indeed human and not some highly-evolved being from another planet. The American showed no signs of stopping or, indeed, wanting to stop on Tuesday, clinching his 20th and 21st Olympic gold medal on another enthralling day of swimming action at the Rio 2016 Olympics.
The first one of the day came in the 200m butterfly, with Phelps winning the grudge match against South African Chad le Clos, before his ridiculous, just plain ridiculous, 21st gold medal came in the 4x200m freestyle relay, winning first place for the USA.
While the relay victory was the icing on a wonderfully-sweet cake for Phelps, Tuesday was all about the 200m butterfly. This was Phelps' chance at redemption, to show the world why he is the undisputed greatest Olympian of all-time.
Having been beaten by Le Clos in the London 2012 Olympics, much to everyone's surprise, Phelps was a man on a mission in Rio. The moment the swimmers came out to the pool, you could see the tension, the drama, the anticipation.
Both Le Clos and Phelps refused to look at each other, or even acknowledge the other existed, even if the only thing that would have been going through their minds would have been "I've got to beat him, I've got to beat him."
After a solid start for both swimmers, it was Laszlo Cseh who led at the first turn, even if the Hungarian soon started to fade. That unparalleled wingspan of Phelps then came to the fore, as the American forged into the lead, with Le Clos right behind him. With the final 50 to go, it looked like being a straight shootout between Phelps and Le Clos, but while the South African faded, the American went didn't to take the gold medal in 1:53.36.
Le Clos (1:54.06) could only finish fourth in the race, with Japan's Masato Sakai (1:53.40) taking silver, while Tamas Kenderesi (1:53.62) of Hungary took bronze.
The celebration from Phelps after the victory said it all, a fist pump and a look that said, yup, "This is why I am the greatest."
The 31-year-old would then go onto take another gold, anchoring the USA home in the relay, for his 25th Olympic medal in total, along with Francis Haas, Conor Dwyer and Ryan Lochte.