An iron fist in a velvet glove, right across the chops of the Irish. The likes of Peter O’Mahony, Conor Murray and Cian Healy, in all their years of service, have never felt a right hook quite like this one. They bowed out with a blowout.

France worked the pitch like Muhammad Ali worked the boxing ring. One of their greatest performances under Fabien Galthie, they were irresistible with the ball in hand, blowing up Ireland’s Grand Slam bid with their Parisian twist on the Bomb Squad.

This was the de facto title decider and, having secured the bonus point with room to spare, the Six Nations title is suddenly France’s to lose. They punched and purred, with Damian Penaud drawing level with the try-scoring record of the iconic Serge Blanco.

‘Just don’t screw it up,’ read the headline on the local Irish newspaper. It was referring to the Taoiseach’s meeting at the White House with Donald Trump next week, although it may as well have run alongside a picture of Antoine Dupont. Oval Office or oval ball, they are two tricky opponents who are hard to predict. Handle them with care because both have the capacity to blow things up when the stakes are at their highest.

Well, Dupont was carried off after 30 minutes, which made this victory all the more remarkable. Rookie flanker Oscar Jegou ended the day in the centres and few would have argued if he had been named man-of-the-match. It was one of those days that ripped up convention.

The Taoiseach may run into Elon Musk in Washington next week – and this is the sort of performance that would come out of the American’s super computer if you asked to produce the perfect rallying display.

France were irresistible as they overcame Ireland 42-27 to take control of the Six Nations

Ireland’s hopes of completing the Grand Slam came to an end in stunning fashion

France’s display was all the more impressive after captain Antoine Dupoint went off injured

Emotions were high as the Irish were led out by their three retiring legends. Rugby fans in their early 20s do not know the game without the likes of Healy and O’Mahony. They are the fabric of an institution that has gone from one that did barely knew what a Grand Slam looked like, to a powerhouse of rugby in the northern hemisphere. Yet this was not the farewell they had in mind.

The anthems here could bring a tear to the driest of eyes, although the announcement that James Lowe withdrew during the warm-up quickly brought things back to reality.

Lowe was replaced by Calvin Nash and the winger was straight into the action, beating Romain Ntamack to Jamison Gibson-Park’s hanging box kick. Ireland dominated the opening quarter. Caelen Doris, tipped as the Lions captain in waiting, won three turnovers and France had to buckle up in defence.

The early territory belonged to Ireland but Sam Prendergast was rag-dolled back over the 22 by Yoram Moefana, before striking the post with his first kick at goal. The French made 81 tackles in the first quarter and kept Ireland pointless. The Irish never recovered.

Dupont had a breakaway try ruled out for a knock on but, with 21 minutes on the clock, against the run of play, he showed his class. Joe McCarthy, a tractor of a second row, was shown a yellow card for pulling back Tomas Ramos. France threw to the tail of the lineout, leaving a big blindside for Dupont to switch back into, throwing a miss pass to set up a try for Louis Bielle-Biarrey.

It was breathless and unrelenting. Bielle-Biarrey’s kick-pass across the face of his own posts left French hearts in mouths. Brian O’Driscoll and Dimitri Yachvilli laughed from the commentary box in disbelief. French swagger at its finest.

Bodies were chewed up and spat out at the rucks. It was like throwing cut offs into a meat grinder. Ligaments stretched to their limits. Dupont wowed his audience with a backdoor pass but then disaster struck. He was smashed by Tadhg Beirne as he tried to secure the ball and his knee buckled. Accidental, said referee Angus Gardner. No penalty. France only had one back on their 7-1 bench and they had 50 minutes to survive with no specialist cover.

Prendergast and Ramos exchanged penalties before the break, with France heading into the dressing room with a two-point lead. Dan Sheehan edged Ireland ahead in the second half from a driving lineout and suddenly Galthie looked like a man under pressure. Those French fans wearing his trademark glasses suddenly questioned their loyalty.

Cian Healy and Peter O’Mahony bowed out in a blowout in front of a home crowd in Dublin

Louis Bielle-Biarrey scored France’s opening try after Ireland had started the match brightly

Oscar Jegou went over to put France on course for their biggest win over Ireland for 15 years

Damian Penaud broke clear to equal the try-scoring record of the iconic Serge Blanco

Healy, pictured, and Prendergast scored late for Ireland but it was not enough for a bonus point

Yet Dupont’s replacement, Maxime Lucu, stepped up to the challenge. He took control of the match in the middle third. He made France’s offloading game tick, leading a 17-point charge during Nash’s 10-minute sin-bin for a high tackle on Pierre-Louis Barassi.

After Paul Boudehent’s try, France unloaded five heavyweight forwards from the bench, turning up the power. Ireland were counter-rucked in their own half and France struck. Penaud galloped out of his half like an animal on the run, before Bielle-Biarrey kicked down the wing and used his pace to score.

Ramos kicked his points before Jegou, shining in the midfield, put his side on course for their biggest victory over Ireland for 15 years. Francois Cros was shown a yellow card but the French siege kept coming, scoring an end-to-end try through Penaud.

Healy and Prendergast scored late on for Ireland yet it was not enough for a bonus point. The hosts were bruised and beaten, knocked to the canvas long before the bell. This one will take some time to get over.