In a recent video, Patrick Mouratoglou built an 'Ultimate GOAT' which included Novak Djokovic, Nick Kyrgios, Roger Federer and Rafael Nadal.
Without a doubt Big Three is the strongest in almost all of the aspects of tennis and Patrick Mouratoglou is aware of that. When building his 'Ultimate GOAT' he included Roger Federer, Rafael Nadal and Novak Djokovic but also Nick Kyrgios what might be a bit surprising choice for some.
However, he picked Kyrgios when talking about the best serve, what is reasonable. Although players such as John Isner, Ivo Karlovic or Reilly Opelka might hit more aces that the Australian, he's probably the best server that isn't higher than 2 meters.
Obviously, Rafael Nadal was named as the biggest fighter as the Spaniard is often referred to as a 'warrior' and the player that other players would let play a rally to 'save their life'. According to Mouratoglou, Djokovic has the best backhand and best return what is also backed by stats. Roger Federer was named as a player with best volley.
Best volley: Roger Federer
Best serve: Nick Kyrgios
Best return: Novak Djokovic
Best backhand: Novak Djokovic
Biggest fighter: Rafael Nadal