LOSING Rory Kavanagh to a red card was arguably a bigger blow to Donegal than leaving the bit of tin behind them in Croke Park.
His unorthodox use of the boot – it was in his hand at the time and still met Darren Hughes' groin – will see him suspended when Donegal travel to Celtic Park in a month's time for a difficult Ulster championship opener against Derry.
To his credit, McGuinness did not pull the traditional managerial 'three monkeys' line and called it straight.
"He's lost his discipline, it's not good enough," he said bluntly. "It had a big impact on the game.
"You represent your county and you've a duty to do the right thing. He got involved in something he shouldn't."
McGuinness stressed that provocation was no excuse.
"He probably was (provoked) but he still has to retain his discipline, that's gonna happen," McGuinness said before getting in a sly dig of his own.
"A lot of stuff went on last year in the Ulster final as well and you can't bring that into the game. You've got to retain your focus and do the right thing."
He was particularly frustrated because Eamonn McGee had similarly transgressed to Donegal's cost in last year's All-Ireland quarter-final against Mayo and also because Kavanagh's moment of madness occurred when they had finally got into the match.
"It was a two-point game and we had the wind at our back, I thought we were in a good position and could have pushed on and won the game but it left it very difficult, they're obviously very good with the ball in hand."
Donegal managed to level things subsequently thanks to a dubious penalty but when Monaghan responded with an immediate 1-1, they were left chasing shadows.
McGuinness conceded that it was his side's worst performance of the year and one that did not instil confidence ahead of the Derry game, even if they were only back 10 days from a week's heavy training in Portugal.
In contrast Monaghan were boosted by their second league title in a row after a repeat of last year's Ulster final victory over the same side.
Once again they outran and outfought Donegal with the sort of pacy, off-loading game that was the Tir Chonaills' trademark in 2012.
In a word they 'out-Donegalled' them and it was that aspect that most delighted Monaghan manager Malachy O'Rourke, whose impressive record with the Farney men is now three trophies in 12 months.
"We really wanted to make sure people didn't say last year was a flash in the pan," he revealed.
"The penalty got them back level but that was probably the biggest thing of the day for us, the way we responded to it.
"We didn't get flustered and went forward and scored the next point and got a good goal after that."
He did a bit of shadow-boxing himself by starting All Star defender Colin Walshe, even though he wasn't listed in the programme.
O'Rourke said Walshe's name wasn't included because he only recovered from this hamstring injury late in the week but that still didn't explain why his name wasn't given to the announcer.
The only dampener on Monaghan's celebrations was the ankle injury to Owen Lennon.
Dick Clerkin proved an ample replacement but Monaghan were arranging an X-ray for Lennon last night and O'Rourke stated that "it wouldn't look great at this stage".
That was the only sour note as the Farney Army marched on.
"We are delighted because when you get to Croke Park you want to perform as well as you can and win where there's a trophy available," O'Rourke said.
"This guarantees nothing down the line but winning breeds confidence so the boys will have a pep in their step."