The hosts actually took the lead through Neal Maupay’s breakaway goal in the 21st minute, but it took a heroic performance from Bees keeper Mark Flekken to keep the reigning champions at bay with a string of stunning saves until Foden struck in first-half stoppage time.
Foden’s goal gave City the added momentum they needed and he grabbed his second eight minutes after the break when he stole in behind Brentford’s defence to glance Kevin de Bruyne’s cross beyond the exposed Flekken.
Brentford, despite being dominated, had fleeting chances to level, especially when Ivan Toney volleyed over from close range, but City were vastly superior and wrapped up the win 20 minutes from time when Foden took Erling Haaland’s pass in his stride to steer the ball past Flekken.