Elsewhere, fellow premiership aspirants Canberra United beat a 10-woman Sydney FC 2-1 courtesy of a ripping long-range strike from Mary Stanic-Floody, and Adelaide beat Western Sydney 1-0.
City (26 points) lead Wellington (24), who have a game in hand on all the other contenders, Canberra (24), Adelaide (23) and Brisbane (22) in the race for the premiership plate.Â
All eyes were on the clash at Casey Fields, where second-placed City, on a two-game losing run, took on third-placed Brisbane.
Brisbane's Kijah Stephenson scored an early brace before McNamara got to work - playing a role in City's first goal, scoring the second, then teeing up Bryleeh Henry for the winner.
In the eighth minute, City goalkeeper Malena Mieres fumbled a straight-forward catch and Aimee Medwin cut the ball back for Stephenson, who chipped it home.
The Roar doubled their lead via another loose pass from Mieres five minutes later.
Momo Hayashi pinched the ball away from Deven Jackson and knocked it forward for Stephenson to rifle home.
City hit back at a corner in the 36th minute after Chloe Lincoln denied a McNamara back-post header, before skipper Rebekah Stott headed home on the rebound.
Five minutes later, Henry slipped through McNamara, who rounded Lincoln - leaping over the diving goalkeeper - and buried the equaliser from a tight angle.
City took the lead when golden boot leader McNamara burst forward down the left and squared the ball for Henry, who took a touch then fired home.
In the 69th minute, Aideen Keane went on a brilliant run, and while her shot was saved, Jackson scored on the rebound..
Brisbane deployed new signing Angie Beard off the bench in the 71st minute, but Keane completed the rout with a ripping strike into the top corner in the 82nd minute.
At Leichhardt Oval, Canberra took the lead when Sasha Grove combined with Michelle Heyman, then skidded a ball through to the back post, where Bethany Gordon tapped home.
Last-placed Sydney hit back after Canberra goalkeeper Sally James and defender Liz Anton collided, with Sky Blues defender Madison Ayson tapping the ball into the empty net.
Sydney defender Kirsty Fenton received a straight red card in the 63rd minute after yanking back Heyman.
Canberra snatched three points when Stanic-Floody let rip on her left with a skidding effort.
Sydney goalkeeper Heather Hinz gave away an injury-time penalty but saved Stanic-Floody's spot-kick.
Later at Wanderers Football Park, Adelaide scored the winner in the 59th minute when Matilda McNamara's shot ricocheted off the post and deflected off Western Sydney defender Danika Matos into her own net.
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