WATCH: Even God on his best day would have feared Peter O’Mahony’s unleashed ferocity

Peter O'Mahony was livid. He was sitting on the bench as bodies dropped all over Dublin and he was livid.

He could help, he knew. He could make a difference. Every single unit was falling to ribbons but the Irish back row was having a blinder. So he sat and he simmered, knowing he could make a difference. O'Mahony was not supposed to be in Dublin tonight. He was set to play for Munster against Treviso, in Limerick. Sean O'Brien's hip tightened up on Thursday and he was summoned back to Carton House. On stand-by. This was a man that was supposed to inherit the Ireland team from Rory Best and he was on stand-by. It was the best they could do for him. He did not like it but he had to lump it. On Friday it became clear - O'Brien wasn't making this dance. Ireland denied the obvious until time overtook them and the call was made - van der Flier in for O'Brien with O'Mahony handed the No.20 jersey. You think he was happy about that? Not a sniff of it. It was all about biding his time though. That time arrived with an hour gone - Ireland were 24-20 behind with Kieran Marmion on the right wing and Joey Carbery at fullback. Ireland were running on fumes but O'Mahony knew he had a part to play. He was pissed off and he channelled it to the very hilt. 65 minutes gone and Simon Zebo has, in effect, won Ireland an attacking lineout. Conor Murray needed ball carriers that would get over the gainline. He turned to Garry Ringrose and then he heard the shout. O'Mahony was coming... Reece Hodge had to take a seat. There was nothing else he could do. O'Mahony twisted, presented, extricated himself from the muddle and got back into the God damn line. 18 seconds later, he carried again and he carried big. Mother of Jaysus, he was up for it. He soaked in three Wallabies and Ireland were close. Two more big carry were needed and first Finlay Bealham, then CJ Stander obliged, to devastating effect. Murray knew he had men over so wide he whipped. He found Simon Zebo and he popped to Keith Earls to finish in the corner. It seemed only fitting that Paddy Jackson would slam over a touchline conversion. 27-24 and no letting up. O'Mahony was still livid. The heavens could hear that roar. It has been six unreal weeks for O'Mahony. He lost a coach, hero and mentor back in Anthony Foley but found it within himself to lead Munster back to themselves and back to a place many felt was lost forever. He had to watch on as Ireland beat the All Blacks in Chicago and handed one back in Dublin. He was surplus to requirements for this game until fate intervened. Post-match Ireland team-mate Iain Henderson told us:

"He would have been champing at the bit to get on and I was 100% sure he was going to be the man to make the impact. "No better man to come off the bench and is a class player and has put in so many class performances before. He went out there to make an impact and Joe talks about subs coming on and making an impact and he made an impact."

He made an impact. He knew he could. We bet he's still livid too. We prefer him that way. Dick Clerkin makes his GAA Hour debut to talk about a wonderful career and argue passionately with Colm Parkinson over Sky Sports GAA. Subscribe here on iTunes.