The former Hartlepool United hitman came on with 15 minutes to go and with Roofing trailing 2-1, thanks to an 80th minute strike by former Roofer James Fairley.
However, it took just 10 minutes for him to make his mark on the game by lashing home within the final five minutes to level the scores and secure a share of the points.
The South Tynesiders actually found themselves ahead in the game as Dennis Knight scored, but Fairley levelled with a great strike.
The Roofers must have thought their unbeaten run was coming to an end when Fairley’s deflected effort beat Lewis Brass late on, but Mackay saved the day – much to the delight of Roofing’s joint manager, Mark Collingwood.
“Mackay would be the first name on the teamsheet for 90% of sides in Division 1, but the form of Chris Winn and Knight has restricted him because those two have got a bit of an understanding going on,” Collingwood said.
“What an option he is to have in the squad, and that’s an option we didn’t have when I first came.
“We had a lot of youngsters and players who couldn’t change games, but he definitely can.
He’s one of those players that can get a goal from a half chance, and his goal has managed to get us a good point against a top six side.”
It didn’t take Knight long to hit the goal trail once again as he put Roofing ahead after just eight minutes.
The visitors won a free-kick out on the left, and Knight whipped the ball in – only for it to miss everyone in the box and squirm through Thomas Dawson’s hands when he came to catch it.
Fairley came back to haunt his old side as he levelled proceedings on 17 minutes.
Knight nearly grabbed his second of the day as he controlled Ethan Wood’s floated ball over the defence, brought it down, and fired a first-time volley across the face of goal.
Roofing were made to pay for their missed chances on 80 minutes. Fairley cut in to a central position from the right, took aim at goal, and his powerful shot bounced off the back of a visiting defender and looped over Brass.
Roofing teams of old might have crumbled when that second goal went in, but not this time. They simply dusted themselves down, pushed forward and went in search of a leveller that came from super-sub Mackay with three minutes left.
Knight broke into the box and forced a good save from substitute ‘keeper Scott Pocklington. However, he could only parry the shot into the path of Mackay, who reacted first to smash the ball in.