Guardiola's men were edged out at Villa for a third league loss of the campaign, raising concern over how much that setback would impact them.
But City have responded with back-to-back wins by despatching Swansea in the Carabao Cup in midweek and collecting three crucial points against a Bournemouth side that has impressed so far this season.
The hosts produced a stylish display to maintain their perfect record against their opponents at Etihad Stadium in the Premier League, now winning all nine contests between the two sides.
The talismanic Haaland was of course integral to their fortunes, marking his opener with a robot celebration.
His double took his tally to 13 in the league this season, both finishes never in doubt after being sent clear by classy assists from the excellent Cherki.
It meant Haaland became only the third player to score two or more goals in four consecutive Premier League home appearances - matching the feats of Robbie Fowler and Luis Suarez.
The 25-year-old will be disappointed, though, not to have a first match ball this term, unable to convert further opportunities before being replaced by Omar Marmoush with eight minutes left.
O'Reilly, constantly supporting the attack with rampaging runs from the back, confirmed the victory when he drilled home from a pass by Phil Foden on the Englishman's 200th league appearance for the club - the 15th and youngest to achieve the landmark.
Rodri replaced Foden, with the Spain midfielder returning to action for the first time in a month following a hamstring injury, while fellow substitute Tijjani Reijnders stung the palms of Petrovic with another attempt.
Arsenal look the team to beat this season after their storming start, but City have slowly got back to the form that will make them title challengers again.