Not until David Silva scored a second goal, on the breakaway five minutes from time, did City and their supporters look truly convinced that they would record their first home league win since September 17.
After Yaya Toure dispossessed Sebastian Prodl, Silva and Raheem Sterling broke upfield, exchanged passes, and the Spaniard convincingly killed off the game from 15 yards.
Argentinian defender Zabaleta, who is out of contract this season and widely expected to leave the club, scored the opening goal that lifted the mounting disquiet around City in these early days of the Guardiola reign.
The goal had been coming, the pressure steadily mounting over the preceding 33 minutes although, until that point, Watford had dealt well enough with whatever City had thrown at them.
But, finally, Nolito threaded a pass wide to the left for Kevin De Bruyne whose hanging, weighted cross found Zabaleta, left unmarked by Adlene Guedioura, and the full-back struck a textbook perfect, first-time half-volley past Heurelho Gomes.
Zabaleta has been used in an unfamiliar midfield role of late by Guardiola, part of the Catalan manager’s wild and wonderful tactical experimentation as he adjusts to life in the Premier League.
But here, he was back to his familiar right-back position as his manager abandoned, for the time being at least, the disastrous three-at-the-back approach that led to the weekend embarrassment at Leicester.
There was still a sting in Guardiola’s selection, however, with his £50 million England defender John Stones dropped to the bench, an indication that the youngster has struggled as much as anyone with his manager’s attempts to stamp his authority and philosophy on the City squad.
De Bruyne’s early probing run ending with a dangerous cross that Jose Holebas cleared well before Silva played in Sterling on the right and his accurate cross found De Bruyne whose curling shot was well saved by Gomes.
The ensuing corner fell to Nolito whose 20-yard strike, from the edge of the penalty area was again stopped by Gomes, although an offside flag was up.
Aleksandar Kolarov, being used as a central defender in Guardiola’s back four, almost created danger at the other end of the field, chipping over from the left wing for Nolito to stretch and head over.
Watford weathered that early pressure, although Prodl earned a yellow card for a hack at Silva and when De Bruyne managed to pick a hole in the defence with a threaded 22nd minute pass that the speedy Nolito raced after, Gomes was equal to the task, turning his near-post shot behind.
The same City pair combined well from the corner although the Belgian’s cross only produced a wild 18-yard from Nolito which sailed harmlessly over. Finally, Watford’s discipline let them down when they gifted the unmarked Zabaleta the chance to claim the opening goal and, before the interval, De Bruyne and Toure would both try their luck with shots.
There was worry for Guardiola when midfielder Ilkay Gundogan was taken off with what looked like a knee injury, being replaced by Fernando just before the interval.
But Fernando’s first meaningful involvement, on the restart, was to set up De Bruyne for a shot which brought City a corner that could have led two trouble for the visitors as Gomes allowed the Belgian’s low cross to squirm through his grasp before being kicked clear by a Watford defender.
Gael Clichy pushed the ball into the area for Nolito who squeezed neatly between Prodl and Darryl Janmaat before his low shot was blocked by a strong covering challenge from Miguel Britos.
And, closest yet to a second goal, Sterling picked up possession just inside the Watford half, powering into a central position, a yard inside the area, from where he unleashed a powerful shot that clipped the crossbar.
Bravo 6; Zabaleta 7, Otamendi 7, Kolarov 7, Clichy 7; Gundogan 6 (Fernando 43, 6), Toure 6; Sterling 7, De Bruyne 8 (Sane 88), Silva 7; Nolito 7 (Navas 80, 6).
Caballero, Sagna, Stones, Iheanacho.
Gomes 5; Janmaat 5 (Success 59, 8), Prodl 6, Britos 6, Holebas 5; Amrabat 6, Capoue 7, Guedioura 6, Pereyra 5 (Zuniga 30, 6); Sinclair 5 (Deeney 71, 6), Ighalo 6.
Pantilimon, Kabul, Watson, Kabasele.