Matt Derbyshire scored the only goal as Macarthur got back to winning ways in the A-League by beating 10-man Sydney FC 1-0.
Derbyshire netted what proved to be the winner in the 36th minute, but his simple tap-in owed much to the great work of Markel Susaeta down the left byline.
Two minutes later Sydney were reduced to 10 when Paulo Retre was shown a red card for a high challenge.
Macarthur could not add to their advantage but still made it three wins out of four following a 4-1 loss to Western United last time out.
They sit second in their inaugural season in the A-League, trailing Central Coast Mariners - who have a game in hand - by a point.
In the day's other game, goals from David Ball and Ben Waine gave Wellington Phoenix only their second win of the campaign, a 2-0 defeat of Newcastle Jets.