Illawarra could have sealed their second straight title with victory at JJ Kelly Park, but will have to wait at least another week after defender Lisa Gilbert and Manly's Lisa Morrison traded first-half goals.

The Wollongong side looked to have sealed three points - and their reputation as the state's best for the second consecutive year - when Jess Cooper tapped into an empty net 15 minutes from time, but the goal was disallowed.

Ash Connor was ruled to have fouled Manly keeper Alyssa Harris, leading to the fumble that allowed Cooper to score. Cooper was then sent off with two minutes remaining after receiving her second yellow card to complete a frustrating outing under lights for the hosts.

Stingrays coach Brett Wallin was disappointed with the decisions.

"Jess was wearing her heart on her sleeve," Wallin said. "To work like she does and get that at the end is disappointing.

"I thought it was a goal. I didn't get a clear view. When you get into that situation, advantage has to go to the attacker."

Cooper will miss at least one week after being booked for time-wasting and dissent.

"Red cards don't get turned over - I'm hoping she only gets a week," Wallin said.

With three rounds remaining, Illawarra (41) stay seven points ahead of second-placed Manly (34), although the Sydneysiders have a game in hand.

"We've got a game up our sleeve, we can lose one and if we win the other two we're premiers," Wallin said. "It would have been nice to have knocked them off tonight but they're making us work for it. Manly deserved something tonight, they scared us a few times."

The Stingrays had a dream start when Gilbert netted early, but the northern beaches side equalised through Morrison's delightful chip 10 minutes before the break.

Manly took heart from drawing level and peppered Sarah Gollop's goal in the dying stages, but the hosts held firm.

The Stingrays reserve grade lost 2-1 after Albion Park defeated Woonona 1-0.