Bruno Fornaroli scored against his old club as Perth Glory snapped a four-match winless streak with a comprehensive 3-0 away victory over Melbourne City on Friday.

Last season's premiers arrived at AAMI Park in last place but turned in a vintage performance against the A-League title contenders.

Fornaroli set the upset in motion in the 27th minute, the ex-City striker nodding past Dean Bouzanis after a deflected Juande shot looped high into the box.

Harrison Delbridge failed to deal with the Uruguayan on that occasion and the centre-back turned Gregory Wuthrich's attempt into his own net moments after the interval.

Erick Mombaerts' men were stunned, and Perth made the points safe 19 minutes from the end when Tomislav Mrcela powered in a header from Neil Kilkenny's cross.

City midfielder Connor Metcalfe later had a goal disallowed for offside as the hosts slumped to a second defeat in three games, while Glory moved temporarily into sixth.