The victory means City will end the night in the top four, four points behind leaders United with a game in hand.
Brighton’s compact formation frustrated City in the early exchanges with only a chance for Kevin De Bruyne on 14 minutes worthy of note.
Ilkay Gundogan played the skipper in but with just Sanchez to beat the Seagulls keeper stood firm and beat the shot out.
But the lowly visitors caused one or two problems at the other end with a couple of dangerous counter-attacks.
Riyad Mahrez was looking in majestic form on the right flank, with some of his passing and deft touches a joy to watch.
It took a piece of brilliance from Foden to finally break the deadlock, with De Bruyne’s pass taken in the youngster’s stride as he cut past one challenge on the left before placing a low shot unto the bottom left-hand corner of the net.
It was his eighth of the season, placing proudly as our top scorer so far this campaign.
City continued to dominate large portions of the game after the break and just before hour-mark, Bernardo came agonisingly close to doubling the lead as he collected a loose ball in the box, nutmegged a defender before shuddering the woodwork with a powerful drive.
Then Mahrez was put clear but the Algerian’s low angled shot whistled past the post.
The missed chances allowed the visitors to grow in belief that they could take something out of the game and as play stretched, the Seagulls looked more threatening.
City looked increasingly tired in the last few minutes with uncharacteristic mis-placed passes inviting pressure from Brighton who finished strongly.
But in added time, De Bruyne latched on to a poor throw-in and Sanchez pulled the Belgian down for a stonewall penalty.
Raheem Sterling stepped up and blazed the spot-kick over the bar - but City held on for a very hard-earned victory.