Coach Pitso Mosimane’s men managed to score two goals in the first half to seal the victory against the home side at the Sugar Ray Xulu Stadium.
Sundowns captain Hlompho Kekana opened the scoring for the defending Absa Premiership champions before Gaston Sirino extended the Brazilians’ lead.
Sirino went from hero to villain when he was given a straight red car for a late tackle in the 83rd minute.
Nduduzo Sibiya pulled one back for the KZN side to give coach Steve Komphela’s men hope of making a comeback.
Arrows missed an injury-time chance to take the game into extra time with a ten men Sundowns team but Mosimane’s men held on for the victory.