The Citizens entered the contest at Villa Park after drawing their previous three league fixtures with Chelsea, Liverpool and Tottenham Hotspur, and the reigning champions have now gone four top-flight matches without a win for the first time since March/April 2017.
Leon Bailey's deflected strike in the 73rd minute was enough for a relentless Villa outfit to claim a deserved victory on home soil – their 14th in a row in front of their own fans to equal a club record.
Man City's best moment in the match came in the 11th minute when Erling Haaland was denied twice by two superb saves from Emiliano Martinez; Haaland's two shots on goal were City's only two attempts throughout the match which is the fewest ever by a Guardiola team against an opponent within Europe's top-five leagues.
Aston Villa, meanwhile, dominated the contest in the final third and had a total of 22 shots on City's goal, the joint-most faced by a Guardiola side in a game within Europe's top-five leagues – Wednesday's defeat at Villa was the Catalan's 535th such match of his managerial career.
In addition, Unai Emery's men won possession in the final third 13 times against Man City, the most ever by an opposition team against the Citizens in a Premier League match under Guardiola.
Man City have now lost each of their last five games without the presence of star midfielder Rodri, who served a one-match suspension along with Jack Grealish, while Jeremy Doku was ruled out through injury.
The Citizens have fallen to fourth in the Premier League table after 15 games, with Aston Villa moving two points above them and taking their place in third, while Guardiola's side are also six points adrift of league leaders Arsenal following their dramatic win over Luton Town on Tuesday.
As well as acknowledging that Villa "played better" Guardiola admitted that his Man City side "struggled" at times in possession, and he has now placed the onus on himself to try to change the dynamics within his team going into the festive period.
"Aston Villa played better," Pep Guardiola told Match of the Day in a post-match interview. "The first half we didn't move in possession and the second half was much, much better and we had chances, but we struggled to find the pass and movements in the right moments.
"After the deflection, we have scored four or five goals with deflections so it is what it is and we have to accept Aston Villa was better and go to Luton.
"Rodri is an important player of course but when he is not there we have to find a way to win without him. Six points [off the top] and we would prefer to be top of the league but we made three draws and lose today.
"In these years we have found a way to win games but we struggled a bit and we have to find a way. It is my job to find a solution. The dynamic changes by winning games. When a team is better you have to recognise it."
Man City will attempt to returning to winning ways when they travel to Kenilworth Road to face Luton Town on Sunday. body check tags ::