The victory gave Mikel Arteta's side back-to-back Premier League wins to open the 2026/27 campaign and another clean sheet, while Villa remain without a point or a goal after their opening two matches.
Saka breaks the deadlock
After a goalless first half, Arsenal eventually found the breakthrough in the 59th minute.
A well-worked attacking move involving Eberechi Eze and Riccardo Calafiori created the opening, with Saka arriving to finish and give the visitors a 1-0 lead.
The goal was Saka's second of the Premier League season, following his strike in Arsenal's opening-day victory.
Arsenal's defence holds firm
Villa attempted to respond but struggled to seriously test David Raya and Arsenal's defence.
The hosts had their best opportunity in the first half when Emiliano Buendía struck the crossbar, but Arsenal otherwise restricted Villa's attacking threat.
Arsenal, meanwhile, were not at their most fluent going forward, but their defensive organisation allowed them to protect the narrow advantage.
The Gunners ultimately saw out the contest to record a second consecutive clean sheet and preserve their 100 per cent start.
Arteta celebrates milestone victory
The match was also significant for Arteta, who marked his 250th Premier League match as Arsenal manager with a victory.
The Spaniard secured his 151st Premier League win in charge of the club, according to Reuters.
The Arsenal manager also introduced new signings Bruno Guimarães and Ezri Konsa from the bench, giving both players their first Premier League appearances for the club.
Arsenal maintain winning start
The result leaves Arsenal on six points from their opening two league matches, keeping the defending champions among the teams with a perfect record.
For Aston Villa, however, the start has been significantly more difficult. Unai Emery's side have suffered two defeats without scoring, following their opening-day loss to Brighton.
Match facts
Arsenal's next Premier League assignment is a London derby against Chelsea, while Aston Villa will travel to face Hull City.