GREATER Western Sydney coach Leon Cameron admits his side needs to be better for longer if it wants to compete with the best teams in the league, after the Giants were overwhelmed by a committed Crows outfit on Saturday night.    

In a see-sawing affair, GWS came back from 21 points down early in the third term to snatch the lead in the final quarter, before the Crows piled on the last four goals of the match to run out 21-point winners.

Cameron lamented his side's inability to close out the game after clawing their way back into it.

CROWS ROLL GIANTS Full match coverage and stats

"We started poorly and ended poorly," Cameron said.

"We got our noses in front halfway through the last, (so) to let them kick the last three or four goals was disappointing.

"They were a bit harder for longer than us over the game."

WATCH Leon Cameron's full post-match press conference

While GWS midfielders Tim Taranto (36 disposals) and Josh Kelly (33 touches) found plenty of the ball, the Giants lost the contested possessions by 20 and the clearances by six.

Cameron said Adelaide were "more committed to the cause" than the Giants were, which was an area his side needed to work on if it wanted to compete in September.

"We were minus 20 in contested possession, that's a pretty good indicator," Cameron said.

"It doesn't mean everything but (it shows) they were just a little more committed for the whole 120 minutes and got the job done when it needed to be done.

"We've got to be better for longer if we're going to compete with really good teams, so that's an area of improvement we need to find."

The Giants weren't helped by the absence of star forward Toby Greene, who was a late withdrawal after failing to overcome a knee injury.

Cameron said he gave Greene up until the last minute to prove his fitness.

"We made a decision today because we thought with the seven day break we might be able to get him up," he said.

"(But) Toby with his history over the last couple of years, we in the end erred on the side of caution.

"He has to get through training next week for him to play. We think that's going to happen."

Meanwhile, Cameron said defender Nick Haynes will be assessed in coming days after sustaining an ankle injury in the second quarter.