The Blues marked the Ivorian's farewell Etihad appearance by breaking the Premier League record for most wins, most goals and most points in a season to cap an unforgettable campaign and a memorable evening.
Danilo, Bernardo Silva and Fernandinho were all on target in the champions' final home match of the season.
With the Blues donning the new 2018/19 home kit, the game began with cheers for every touch Yaya made.
City started brightly, moving the ball around quickly despite the eight changes Pep made from the side that drew with Huddersfield Town at the weekend.
Bernardo Silva was at his twinkle-toed best, tormenting Seagulls’ left-back Gaeten Bong every time he received the ball.
The Blues went agonisingly close to opening the scoring when Fernandinho’s low cross was turned goalwards by Ilkay Gundogan only for Shane Duffy to make a superb clearance and prevent a certain goal.
The home faithful didn’t have to wait long until the deadlock was broken, however.
Leroy Sane picked the ball up in space in the centre circle and fed through an inch-perfect ball for Danilo who raced clear before planting a low drive past Matthew Ryan with aplomb with 16 minutes on the clock.
That lead lasted just four minutes as the Blues conceded a goal that had Pep Guardiola jumping in frustration as Claudio Bravo was drawn wide in his box and though he delayed Davy Propper momentarily, the Brighton man still managed to get a cross in that Leonardo Ulloa nodded home with Danilo stranded on the line.
City responded well with Gabriel Jesus going close to turning in Yaya’s burst into the box and low cross and Aymeric Laporte was unlucky to see a fierce low drive hit a defender before going out for a corner.
In a bright, entertaining game, the Blues regained the lead on 34 minutes as Sane’s low cross was drilled home by Bernardo – the goal that also set a new Premier League record of 104 scored – and counting.
The second half began as the first had ended, with City dominant and the visitors eating up time whenever the opportunity arose.
Fernandinho, playing in a more advanced role, came close to extending the lead ten minutes in as he controlled the ball and span in the box only to be denied by an instinctive block by Ryan.
But Brighton should have levelled just before the hour-mark when Jose Izquierdo’s low shot was palmed out by Bravo resulting in moment’s pinball in the six-yard box, ending with Anthony Knockaert blasting over with the goal at his mercy.
Finally, the champions put the game to bed on 72 minutes when Sane completed a rare hat-trick of assists as he picked out Fernandinho from the by-line an the Brazilian made no mistake with a low shot into the bottom corner.
Of course, what the home fans were craving was a Yaya Toure goal in the time that remained!
Sane came close to setting him up, but Yaya's shot from close range was straight at Ryan with the whole stadium on their feet.
Yaya left the pitch not long after to a loud and long standing ovation as City fans paid tribute to a genuine Club legend.
There was enough time left for Danilo to rattle the bar with a sublime free-kick, but the night was very much Yaya Toure's.
Anthony Knockaert's miss from close range at 2-1 could have brought the Seagulls level - instead City increased the lead with the next shot on goal.
City Matchday App Star Man: Yaya Toure
Landslide vote for tonight’s skipper – no surprises there - but fully merited.
What it means:
City move 20 points clear of second-place Manchester United and within three points of a century.
The Blues also set a new goal-scoring and point record in the process.
There is still a record points-winning gap and goal difference to aim for.
Leroy Sane has now moved level with Kevin De Bruyne with 15 assists for the season.
City travel to Southampton to wrap up an unbelievable campaign.
Mark Hughes’ side are unlikely to be mathematically safe from the drop so expect the hosts to adopt a cautious approach.