Melbourne City have become the first team to claim four W-League championships, completing an unbeaten season with a 1-0 victory over Sydney FC at AAMI Park.

City captain Steph Catley scored Saturday afternoon's only goal in the 15th minute and was named best afield for a superb individual performance, although Sydney more than held their own against the premiers.

"The fact that we still got over the line, even though we might not have played our best football just shows how much this team wants to win and I think, at the end of the day ... we deserved it," Catley said.

The victory completed a tremendous season by City, who won 11 of 12 regular-season games, drawing one, and conceded just five goals across their entire campaign while scoring 33.

"I would like to look at it as just a reward for six months' hard work and sacrifice and I think, at the end, we deserve both a premiership and championship," coach Rado Vidosic said.

Sydney started the better of the two sides but City drew first blood.

Catley and Emily van Egmond played a clever one-two, allowing Catley to take a touch and drive a shot towards the far corner. But Aubrey Bledsoe's poor attempted save bundled the ball into the net.

An Alanna Kennedy howler almost handed City a second goal in the 32nd minute.

The Matildas' centre-back blindly passed across her defence, with Claire Emslie pouncing - only to hit her shot straight into an advancing Bledsoe.

Two minutes later, Kyah Simon hit the crossbar with a cross-turned-shot.

Sydney had a penalty shout waved away soon after when Sofia Huerta's cross into the box appeared to hit Catley in the face, only for replays to show it had hit her elbow.

The Sky Blues spurned a golden opportunity to draw level in the 49th minute.

Ally Green's brilliant cross-field ball landed in the path of Veronica Latsko. But goalkeeper Lydia Williams made herself big to block Latsko's shot, with Ellie Carpenter on hand to clear the ball off the line.

City butchered another chance to double their lead on 57 minutes.

Emslie put Simon through on goal with an excellent ball but the Matilda blasted her shot off target.

Williams denied Sydney substitute Princess Ibini with an impressive save in the 80th minute.

Bledsoe almost handed City a second goal when her injury-time clearance bounced off City's Milica Mijatovic and just trickled wide of goal.

"I'm super happy and super proud," Sydney coach Ante Juric said.

"Unfortunately, we didn't win but I can't ask more than what the girls gave - and to lose when you've given everything, it's no issue.

"We tried everything, we gave it everything and City kept us out - so it's a credit to them as well."