So, after seeing his summer signing sent off for throwing a punch towards the end of the first-half, the Dundee United manager chose to use an injection of humour to defuse the row surrounding his controversial departure as his league leaders dealt admirably with his loss to defeat Queen of the South and remain in pole position in the Championship.
McKinnon watched the 21-year-old former Celtic player receive his marching orders in 37 minutes for taking a swing at Shaun Rooney, the Queen of the South full-back who’d been guilty of fouling him.
McMullan was sent packing by referee Nick Walsh, but the leagues leaders still managed to rally to win through substitute Scott Fraser’s 68th minute goal after Scott McDonald’s early opener had been cancelled out by Callum Fordyce’s 25th minute equaliser.
“If it’s a red-card then so be it,” said McKinnon afterwards whose side have won their first two matches of the new league season.
“But he must be fighting at bantamweight – or the lowest weight there is.
“It’s out of character if he has thrown a punch but I felt the referee could have dealt with it earlier.
“Their guy was pulling him and pulling him and Paul’s still trying to get away so he gets frustrated.”
United took a sprightly 17th minute led. It was simple in creation as former Australian international McDonald, another of the club’s summer captures, celebrated his first goal since arriving at the club.
McMullan raced to the bye-line before crossing for McDonald who stuck out his knee to bundle the ball past Alan Martin in the visitors’ goal.
Fordyce, though, equalised when the home team failed to clear a simple free-kick and the defender calmly steered a left-foot shot low past home keeper Harry Lewis.
Things escalated eight minutes before the interval when Queens stopper Rooney was penalised for pulling back McMullan.
Despite getting the foul in his favour, McMullan suffered a rush of blood to the head as he threw a punch to leave Walsh with no other option than to showing him a straight red-card.
From then on it was a case of whether Queens could actually make the extra man count after the break but substitute Fraser struck having only come off the bench a mere five minutes earlier.
McDonald played in Billy King who set free Fraser whose low left-foot shot found its was past Martin.
Queens, though, wasted a golden opportunity to level in 73 minutes when substitute Chris Kane found himself clean through, but shot straight at Lewis, who rescued the hosts again in 86 minutes by denying Jordan Marshall by turning his net-bound left-foot shot round the post.
“I’m both frustrated and disappointed at not taking something from the game,” reflected Palmerston manager Gary Naysmith afterwards. “We created a lot of chances against their ten men but it just wasn’t to be.
“I think whoever finishes above Dundee United will win the league.”