"Yeah I've qualified for 15 years but I don't know how many years I've completed the tournament", Nadal said.
Speaking at the O2 Arena, he said: "I need to go day by day".
With the ATP Finals in London beginning on Sunday, Friday saw group photo time, and more importantly, group selfie time.
"We're all young", said the 21-year-old.
Top seed Nadal, 33, who won the French Open and beat Medvedev in the final of the US Open, said it was an exciting moment for tennis.
Rafael Nadal is set on ending 2019 as world number one despite doubts over his fitness heading into the ATP Finals.
Camion charnier en Grande-Bretagne: les 39 victimes identifiées étaient vietnamiennes
Le conteneur était arrivé par ferry au port de Purfleet, sur la Tamise, en provenance de Zeebruges, en Belgique. La police vietnamienne a arrêté dix personnes soupçonnées d'être impliquées.
"There could be a distinction between that and in actuality being a national hero in your nation already and being a high 10 participant within the area in tennis, which is irritating to cease".
The US Open victor is in London ahead of the year-ending tournament as he recovers from an abdominal tear sustained last Saturday. But we appreciate each one's game, each one plays differently and it's quite interesting to see so many varieties.
"I think that's great that they're part of the finals".
"I mean, we are the future, we are the ones who [will be] filling the stadiums, and we're also going to create the future for our sport, together with other younger players".
Zverev acknowledged that Federer, Nadal and Djokovic still deserved their place at the pinnacle of the sport.
"I think it's a great message for the sport", he said.
Clippers not breaking load management rule with Kawhi Leonard
Last season's roster thrived by dominating bench minutes, but that hasn't been the case so far this year. The Clippers' defense held the duo scoreless in the fourth quarter on a combined 0-for-8 shooting.
The Spaniard pulled out of last week's Paris Masters at the semi-final stage and is nursing an abdominal strain as he gears up for his first match on Monday. "Right now the main goal is to be ready on Monday following the protocols that the doctor gave me".
"At the end of the day I think with age and experience I can be confident about what I do in training", Federer said. "They have good competition between each other in front for the next years".
Roger Federer has won four titles in 2019 but his season will be remembered for the one that got away at Wimbledon, where he held two championship points on his own serve before eventually succumbing to Djokovic.
Berrettini is the making his ATP Finals debut and joining some elite company. "But the other guys are still there, they're still playing the best tennis in the world, they're still better than us, because they're the ones winning the biggest tournaments".
"About a of the younger guys are no longer right here but however I am certain will attain very nearly as we state".
"But I really hope I will be able to serve every single day a little better, and my hope is to be on Sunday serving normal", he added.
Courteney Cox and Matthew Perry show us they're still 'Friends'
Well, whatever the project will be, we hope that it just happens soon. "We're working on something". Lisa Kudrow , best known for playing Phoebe on the show, added, "Lucky lucky #beautifulpeople ".