Donegal are no strangers to nightmares themselves. They were in turmoil last year. Between managerial changes and heavy defeats, they looked a team in disarray.
But with a Division Two title in the bag, they have steadied the ship under McGuinness, and on Saturday they looked an entirely different animal to the disillusioned bunch who were ushered out of Ulster by Down last year.
Collectively they were a joy to behold. Ryan McHugh, absent last year, looked back to his electrifying best, Jason McGee produced a massive midfield performance to stand up to Derry’s Conor Glass-Brendan Rogers axis while Brendan McCole ensured Shane McGuigan had one of his quietest games in a while.
O Baoill even managed to do to Lynch what he did to Fermanagh’s Ross Bogue earlier this year.
But McGuinness – back in the Ulster Championship for the first time since the 2014 final – was not about to carried away given what lies ahead.
He had six months to fine tune his masterplan for Derry. He has just a week to plot either Tyrone or Cavan’s downfall.
“I hope that it helps a lot, I hope it will add a lot to the belief, but the problem is we have an eight-day turnaround,” McGuinness told a large group of reporters as the temperature plummeted outside the Celtic Park changing rooms.
“We’ve got to get ready to go again and there’s no time to sit on anything. We’ve got to get straight into it now.
“It feels good to take a breather tonight and get up the road to watch the game tomorrow. Knowing you’re through is brilliant but as soon as you know who’s coming out of that game, it’ll be full-on for another week.
“It’s very difficult to do your job in a week. It’s almost impossible. It’s a bandage over a dam situation.”
McGuinness, as he has done so often in the past, edged the tactical battle. His players utilised Shaun Patton’s kick-outs to build their attacks to great effect before the goalkeeper was forced off in the second half with an injury.
The Donegal boss is regarded as one of Gaelic football’s master tacticians, but he admits his squad may need to draw more on energy and momentum than tactical innovation before next week’s semi-final.
“We must try, I think, to harness the energy from the performance as opposed to the tactical build-up for the next one,” observed McGuinness, who improved his tally over Harte in championship fare to 4-0.