City moved top of the table with a one-sided thrashing of the Hornets, continuing an incredible week which has now seen them score 15 goals without reply in three matches.
Aguero's treble took him on to 175 goals in his City career, and should he repeat that feat against pointless and goalless Crystal Palace next weekend then he would overtake Eric Brook as the club's all-time leading scorer.
"Hopefully that will happen very soon, and hopefully we can have a big celebration. Hopefully the club can do that one day soon in the stadium at the game. He's a legend, and it's a part of history in the club," Guardiola told reporters.
"Listen I always think he works hard. But he's a guy I encourage to play, not just to score goals. I don't want just two or three players defending or trying to score goals, I want everyone defending and everyone attacking. I want to see every player move towards the ball, especially the strikers."