The 26-year-old's brilliant diving save at full stretch from a shot on the turn by Aberdeen striker Zola in the early stages of the game at Pittodrie served as a timely demonstration of his ability.
However, from there on in Fox was helpless as a combination of poor Thistle defending and clinical Aberdeen finishing had him picking the ball out of the net four times.
The result makes Derek McInnes's side Celtic's nearest challengers, four points short of Neil Lennon's men at the top of the league and Aberdeen, who were watched by more than 10,000 fans, have won four games in a row and not conceded a goal in that period.
Thistle manager Alan Archibald had spoken before the game about exploiting Aberdeen's few weaknesses.
He had witnessed, first-hand, how well the Dons rear-guard dealt with aerial balls in their
2-0 League Cup win at Motherwell
and perhaps that was the reason for a low driven corner kick from which Gabriel Piccolo almost finished off at the back post.
Fox's clean-sheet hopes ended midway through the first-half, but the blame had to lie with his defensive wall at the free-kick conceded by Aaron Taylor-Sinclair.
For when McGinn neatly curled home into the near post from 22 yards, a ducking Stuart Bannigan meant the ball had a much clearer trajectory into the back of the net.
It was a welcome first goal in 12 games for the Northern Irishman, who played a key part in setting up his team's second before the break.
McGinn waited patiently for a surging run from Peter Pawlett, who upon reaching the by-line drilled the ball low across the goalmouth for Zola to extend a leg and tap in at the back post.
Partick Thistle keeper Scott Fox made a spectacular save to deny Calvin Zola early on.
Pawlett's challenge on Kallum Higginbotham earned him a yellow card and stoked the visitors a little as they began the second half looking to take the game to Aberdeen.
That rejuvenation was momentarily quelled by Hector's arrowed shot which put the hosts three ahead in emphatic manner.
But Partick nearly responded immediately through a wonderful piece of opportunism when Higginbotham's spectacular strike straight from the kick-off bounced off Jamie Langfield's crossbar.
The Aberdeen goalkeeper was scrambling because of Higginbotham again minutes later when the Englishman's deflected strike nearly looped in.
McInnes's men ended the night how they began it, though.
Mexican defender Piccolo denied Hayes a simple tap-in before a slick passing move ended with Hector delivering a fine cross for McGinn to meet first time and convert brilliantly - his first goal from open play this season.
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