City stuttered to a third-place finish in Guardiola's debut season while failing to produce the stylish play of its manager's former sides, but a second straight offseason of significant personnel changes appears to be paying dividends.
Man City however have started the season brightly and look good value to add some silverware to their collection come next May.
Victory means City have now scored 15 goals without reply in their last three games after big wins over Liverpool last week and Feyenoord in midweek. "I need him, the team needs him".
Manchester City could welcome captain Vincent Kompany back from a calf problem.
Silva, who has hit the ground running with eight points from a possible 12 since joining Watford, will hope his side can replicate their recent defensive solidity.
The situation has echoes of the final game of last season when then boss Walter Mazzarri was without six centre-backs for the visit of Manchester City. "The score is heavy but it is not easy", says Watford manager Marco Silva. A lot of it is down to Heurelho Gomes, the veteran Brazilian goalkeeper who has been a rock between the sticks for the Hornets. This includes an exciting 3-3 tie against Liverpool to open the season.
Aguero's hat-trick - his sixth in the Premier League and 10th for City - has moved the Argentine only two away from Manchester City's all-time scoring record of 177, set by Eric Brook between 1928 and 1940.
Pep Guardiola says Manchester City are beginning to remind him of his great Barcelona side after a dominant week domestically and overseas.
Unbeaten Watford can go top for the first time in 35 years by beating Manchester City today. Man City can bring on midfielder Leroy Sane just as defenders are tiring, which spells trouble for opponents.
"Tomorrow, for example, is a big test for us".
There was the memorable FA Cup game in January 2014 when Fernando Forestieri and Troy Deeney put Watford 2-0 up at the break and it was not until the 78th minute that Sergio Aguero pulled City level, and the 86th minute that Aleksandar Kolarov's put them ahead. Minutes after a denied penalty shout from Newcastle, Lascelles rose high over the defense on a corner to meet another Ritchie cross and nod it into goal for the 2-1 lead and the eventual win.