Clive Gauci put Sirens ahead on the 23rd and Johan Castano equalised on the 31st. However Marco Antonio Morgon Filho made it 2-1 on the 67th and Michael Micallef sealed the issue with another goal three minutes from time.
In another match, a brace by Alexis Ramon on the 23rd and 67th gave Gudja United their first win as they defeated Swieqi United 2-0.
Sirens lead the way with 8 points, followed by Santa Lucia on 7, Gudja 6, Mqabba, Lija and Pembroke 5, Swieqi 4, Naxxar, Vittoriosa, Zejtun and Marsa 3, Qrendi and Zebbug 2 and San Gwann 0.