The introduction of target man Sam Cosgrove at the break provided a focal point that had been markedly absent from the visitors’ attack in the first 45 minutes but it was the pace of Gary Mackay-Steven which helped pave the way to McGinn’s 69th-minute leveller.
Both players stood over the ball after the former Celtic and Dundee United winger’s dash towards the penalty box had been halted abruptly by despairing Saints midfielder Blair Alston.
But it was McGinn who seized the opportunity to sweep the 20-yard free-kick over the defensive wall and beyond the reach of keeper Zander Clark, who had brilliantly denied Cosgrove an equaliser minutes earlier from a header at point-blank range.
Relieved McInnes joked that McGinn’s conversion rate was probably one in 40 but the attacker’s belated first strike of the campaign proved timely against a Perth side offering much more in terms of flair than last term.
The Irishman admitted ignoring a bid to pull rank by his skipper, Graeme Shinnie, before executing his spectacular strike.
“Shinnie was shouting before the free-kick that it was definitely for a left-footer but I felt good in the game and felt confident,” he confided.
“I’d had a few shots leading up to it and it was in a nice position. I was delighted to see it hit the back of the net because I was definitely due one.
“Shinnie was never getting it. It was always me or Gaz who was hitting it. He was standing up for the left-footers but I’m delighted to get the goal to get us back into the game. On another day we could have gone on and won.”
It has been a slow start to the campaign for the Pittodrie club, having garnered just six points from 15.
And they were vulnerable after McMillan powered home a near-post corner delivered by Liam Craig, who was replaced at the interval following a difference of opinion with his manger, Tommy Wright.
Both sides had chances and penalty claims ignored by referee Willie Collum. A point apiece was about right in an entertaining contest.
“We’re maybe lacking those two or three games on the bounce where we win and get that consistency of being comfortable in games,” said McGinn. “We maybe just need a few on the bounce to click as a team to get that confidence.
“We need to keep a clean sheet to start with. If we’re not keeping clean sheets it makes it more difficult for us as a team. On another day we could have won but it was maybe just that wee bit of luck in front of goal that we lacked. I know with the players that we have that we’ll score more goals than we concede.”
Mackay-Steven and Perth half-time substitute Ross Callachan both felt hard done by when referee Collum waved away spot-kick appeals, with Dons supporters targeting the SFA for their ire throughout the match, with defender Michael Devlin’s suspension standing in the wake of a controversial appeals panel verdict.
Ex-Hearts midfielder Callachan was asked if he felt the officials had been placed under pressure from the vociferous Red Army. “Only they know that. But I think these referees will be used to fans giving them all sorts of abuse and stuff so I can’t see that changing,” admitted the Saints debutant, who was delighted to be involved on a match day after finding himself in the shadows at Tynecastle this term.