Tim Cahill's injury compounded Melbourne City's misery as their 100 per cent record this season was ended by a 1-0 loss to Sydney FC, who remain unbeaten and are now top of the A-League.
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Former Everton star Cahill limped off with an ankle injury in the first half of the contest at AAMI Park, with City coach Warren Joyce confirming the Socceroos legend went to hosptial to have scans before full-time.
The 37-year-old's injury will be a major concern for Australia ahead of their World Cup intercontinental play-off against Honduras, with the first away leg scheduled for next Saturday.
Ange Postecoglou's men are scheduled to board the plane to Honduras on Saturday morning.
Joyce could not confirm details of the injury after the match but Sydney FC and former Soceroos coach Graham Arnold added: “I didn’t see it, I just heard him scream when he went down just in front of the bench.
“When he walked off I went over to him to shake his hand and see if he was all right and he just said he’d rolled it."
Cahill scored a double in Australia's victory over Syria last month to progress to the playoff against Honduras.
City's frustrations were compounded when Luke Wilkshire volleyed home Michael Zullo's cross just shy of the hour to secure a win that sees Sydney, who are now 14 league matches unbeaten, leapfrog their opponents atop the table.
59' GOALLLLLLLLLLLLLLL!!!!!! WILKSHIRE!!!!!!!!! 0-1 #SydneyIsSkyBlue #MCYvSYD pic.twitter.com/CXyugd8u9G
— Sydney FC (@SydneyFC) November 3, 2017
The hosts had responded well to Cahill's injury and Nick Fitzgerald felt he was fouled in the area by Jordy Buijs, before the same man struck just wide of the right post from 20 yards.
But Sydney had the lead when Wilkshire fired Zullo's delivery into the ground and watched the ball bounce into the top-left corner.
Ross McCormack failed to sort out his feet in time when Fitzgerald's low, fizzed cross needed just a touch as, despite pushing hard for the equaliser, Warren Joyce's side saw their unbeaten start to the campaign come to an end.