In a game which saw one penalty scored, another missed, eight yellow cards, two red cards on the pitch and a third in the tunnel, a last-gasp equaliser and repeated confrontations between the respective benches, the pair headed home experiencing widely contrasting emotions.
It is a fair bet referee Mike Dean did so to lie down in a darkened room after what must have been one of the busiest afternoons of his career.
From the moment he booked Black Cats skipper Lee Cattermole for a wild challenge on Cheick Tiote with just 40 seconds gone he was a central character, and he left the field to be greeted by accusations that he had received a visit from the Newcastle coaching staff at half-time.
Asked about the straight red card Cattermole received for confronting Dean after the final whistle, O'Neill said: "Possibly in mitigation we had heard that some of their staff had visited the referee's changing room at half-time.
"Of course, we are not party to what was said, but Lee's mitigating circumstance was that he felt a lot of decisions had gone Newcastle's way in the second half.
"That may well be. It doesn't necessarily mean I agree with it, but if you have a little look back, Newcastle themselves would consider themselves lucky to have 11 men still on the field if the referee had continued according to the way he started the game."
Pardew, whose goalkeeping coach Andy Woodman was dismissed at half-time after a spat with Sunderland fitness coach Jim Henry, insisted no-one had visited the referee.
He said: "I can tell you that's completely untrue. None of our staff was allowed in the referee's room. No-one tried to enter it and no-one entered their dressing room.
"I heard that rumour and it's not right."
The feistiest Tyne-Wear derby for some time began with Cattermole's lunge at Cheick Tiote and never really dropped in tempo as Sunderland capitalised on an impressive first-half display by snatching a deserved lead.
Sunderland led through Nicklas Bendtner's 24th-minute penalty after Mike Williamson was penalised for pulling Michael Turner's shirt, but were reduced to 10 men in the 58th minute when Stephane Sessegnon elbowed Tiote.
But for all the Magpies dominated thereafter, central defenders John O'Shea and Turner kept them at bay until Fraizer Campbell tripped fellow substitute Shola Ameobi.
Simon Mignolet pulled off a superb save to keep out Demba Ba's penalty, but in the first minute of stoppage time Ameobi steered Williamson's flick-on home.
Pardew, who had celebrated prematurely when the spot-kick was awarded to the clear annoyance of the Sunderland bench, said: "Listen, let's not all get carried away here. This has been a great game of football.
"What happens on the bench sometimes gets out of hand, silly things are said. It happens all the time and you just get on with it.
"I have never done that before. It just goes to show that the pressure of the game can get to even the oldest of managers like myself. I was feeling like 58 today rather than 50."
O'Neill, who indicated he would not be taking up the offer of a glass of wine with Pardew, was able to take plenty of positives from his first taste of the derby.
He said: "It was everything that people had told me about, everything, absolutely everything.
"Hostility, which I am kind of used to - that's even from my own fans - fervour, everything, everything.
"In a perverse sort of way, I was enjoying it - it had to be really perverse - but there was obviously disappointment at the end."
That disappointment was compounded by the fact that both Sessegnon and Cattermole will now miss the FA Cup quarter-final trip to Everton through suspension.