Metcalfe combined with Jamie Maclaren before applying the finish seven minutes into the second half at Dolphin Stadium on Tuesday.
The midfielder's fifth A-League goal was enough to seal all three points in Kisnorbo's first game as head coach after he replaced Erick Mombaerts.
Adrian Luna was shown a second yellow card for a foul on Rahmat Akbar with just over 20 minutes to go, but last season's beaten Grand Finalist City held on.
Macauley Gillesphey's header grazed the top of the crossbar and Riku Danzaki went close to a late equaliser, but Brisbane was unable to avoid defeat in its new home.
