The Dundee United winger, jettisoned from Gordon Strachan's Scotland squad in midweek, has struggled for form since returning after the summer.
He was widely expected to head to England on the back of his exploits last term and disillusionment over still being at Tannadice could have taken root.
But Blackburn Rovers are understood to have sent a delegation north to watch him help dismantle St Johnstone and he certainly gave them something to consider ahead of the closure of the transfer window next week.
Mackay-Steven scored his side's third in the wake of goals from Keith Watson and David Goodwillie, and set up Stuart Armstrong for the fourth
Armstrong has no doubt his team-mate can be a success in England, but last night urged him not to jump at the first chance to get away.
"I am sure he will end up down there one day," the midfielder said. "You have to make sure you choose the right club, though, and there is a bit of luck involved, but I am sure Gary will do the right thing when the time comes."
For all the debate over Mackay-Steven, the result is a tremendous fillip for Jackie McNamara.
Ahead of this eruption of goals, the Tayside club hadn't won a match at home since April 6. Indeed, they only managed four victories at Tannadice in the league last season.
A goal in the third minute certainly eased any early jitters and allowed the Arabs to benefit fully from players actually appearing to remember they do possess a modicum of talent.
Watson's opener was aided by a sizeable dose of luck. He did everything right in collecting a Ryan Dow pass on the flank and cutting inside to release a powerful drive with his left foot.
But there is every possibility it would not have beaten the outstretched Steve Banks, standing in for the injured Alan Mannus, to land in the far corner, had it not been for a deflection off Paddy Cregg.
It was also Cregg, replaced at half-time by Chris Millar, who conceded a free-kick on the Main Stand touchline with a foul on Mackay-Steven. That let Dow send a high ball towards the left-hand side of the area.
Watson got the jump on his marker to send a deflected header into the centre of the area. Goodwillie, inexplicably untracked, stole in to place a crisp header past Banks and score the first goal of his second spell in United colours.
"He took his goal well and his all-round play was a lot better," said McNamara. "He held up the play and looked a threat - the goal has taken a bit of weight off him."
Andrew Robertson, promising and brave, surged up the left flank to create the third five minutes before the break after getting the ball from Calum Butcher, picking out Mackay-Steven inside the area with a slide rule pass.
This living, breathing box-of-tricks has been off-colour in recent times, without doubt.
However, the receptors inside his brain seemed to fire back into action at the scent of a goal and he produced a low effort from a tight angle with his first touch that squeezed under Banks to roll over the line.
Eight minutes into the second half, he chose to turn provider when delivering a low ball in from the left that invited Armstrong, powering into the area like a bull on the Pamplona cobbles to smash the ball home in imperious fashion. Thing is, he didn't. His effort was a mis-hit, but still managed to spin off the turf and evade the despairing dive of Banks.
Steven MacLean and Nigel Hasselbaink missed two fine chances for Saints late on, but manager Tommy Wright made few excuses. "Before the game, I felt we were a bit flat in the dressing-room and saw it coming," said the Northern Irishman.
"There was a severe lack of energy and our work off the ball was disappointing as well."