The 21-year-old won the Cazoo Open de France and posted seven other top-10 finishes as he ended his debut season in 17th position on the Race to Dubai
United climbed to seventh place on 16 points from 12 games after stretching their unbeaten home run against the Seagulls to 12 matches in all competitions. Brighton slipped to 11th place on 15 points.
Pereira fired United ahead in the 17th minute with a fortuitous goal, as his shot from inside the penalty area took a heavy deflection off Dale Stephens and left Brighton goalkeeper Matthew Ryan stranded.
Propper then bundled the ball into his own net two minutes later as an inswinging free kick from Fred caused havoc in Brighton's six-yard box. The goal was awarded after a VAR check.
Lewis Dunk pulled one back for Brighton in the 64th minute with a close-range header, but Rashford restored United's two-goal advantage two minutes later when he blasted a shot from 12 metres in off the underside of the bar.
Meanwhile, Wolverhampton Wanderers beat Aston Villa 2-1 in Sunday's Midlands derby with goals from Ruben Neves and Raul Jimenez taking them into the top eight in the Premier League.
It was a difficult afternoon for Villa from the moment they lost goalkeeper Jed Steer to injury after only five minutes.
Wolves dominated and the only surprise was it took them until nearly halftime to go ahead, Neves giving replacement keeper Orjan Nyland no chance with a thumping drive.
Another injury for Villa led to left back Matt Targett being replaced before the interval but the visitors showed plenty of endeavour after the break to stay in the game.
Villa even threatened to equalise on the odd occasions but Wolves effectively sealed the points when Jimenez, guilty of wasting some earlier chances, fired into the corner after good work by the dangerous Adama Traore.
There was some consolation for Villa when Trezeguet halved the deficit in stoppage time but it was too late.
Wolves's first Premier League win over Villa for eight years lifted them to 16 points from 12 games while Villa remain fourth from bottom with 11 points.
The Fed and the ECB have made clear that they intend to roll back quantitative easing by gradually reducing their bond holdings