City's third came on 32 minutes when Jesus' deflected shot only went as far as Foden. Sanchez did get a hand to it but the power of the England international's shot was enough to take it into the net.
No City player has scored more than Foden's 20 goals since the start of last season across all competitions.
Foden is still more than capable of excelling as a central midfield playmaker, as he proved when impressing for England against Andorra in the position earlier this month, but it seems for City he can have a greater impact out wide.
"I'm enjoying it (the new position)," Foden said. "I can drop deep and get the ball and pick the passes off. It's a new role for me and I can say I'm really enjoying it.
"It changes game-to-game. Sometimes I stay higher than normal, but this game they went man-to-man so I dropped a bit deeper and I thought we used the extra man well."
After the match, City boss Pep Guardiola said: "I know what it means coming here against this team, against this manager and this stadium and win here.
"It is a good lesson that in football it must be played with the ball and when you don't have it you suffer. Brighton are so hard to play against for 90 minutes. Against another opponent the game would be over (at 3-0), against this team it was not over."
Brighton pulled one back from the penalty spot after 80 minutes when Alexis Mac Allister beat Ederson, but Riyad Mahrez added a late fourth to put the result out of reach for the hosts and City secured the three points to move into second in the table above Liverpool and behind leaders Chelsea.