The Sydney Flames have become a threat in the WNBL after ticking the reigning champion Townsville Fire off their hit list with ease.

Sunday's 90-77 result handed Sydney their fourth straight win - their best season start since 2010-11.

It hurt fans in Townsville after they had watched their team unfurl its Championship Banner from last season at the Fire Pit Stadium before the game.

The Flames' defensive game was strong from the jumpball, forcing Townsville (1-2) to take difficult shots and miss as the shot clock ran down in their first two offensive plays.

It gave Sydney an early four point lead and Townsville remained in the deficit for the remainder of the game.

"The result is not really the thing that's disappointing. I think it's just more how we've played our first few games," Fire coach Shannon Seebohm said.

"We're just lacking.

"Teams are getting some really easy shots right now, and I just feel like we don't have a lot of cohesion".

Townsville stayed well in the game and trailed by five points at halftime before Sydney's Jazmin Shelley got going.

She was critical in the third quarter when the lead stretched out by 22 points, and finished with 26 points, six rebounds, six assists and three steals.

"Jaz has been great for us in all four games," Flames coach Renae Garlepp said.

"But I think probably most impressive today was her defence.

"We wanted to double down on defensive and be a bit more gritty and move with the ball a bit better than we have."

The Flames were without their star Ally Wilson (knee), but the depth of talent in their line-up showed through 25 points shot from the bench. Agnes Emma-Nnopu was one such player, and dominated off the glass with six rebounds.

"I think that this team was recruited with in mind that any player can step up on any given night," Garlepp added.

"Ali Wilson's an awesome player. But I just kind of feel like we back the players we've got".