Didier Deschamps responded decisively to a tactical mistake as Antoine Griezmann helped France to make their first real statement of intent at Euro 2016 on Sunday.
A huge shock was in the offing going into half-time at Stade de Lyon, as the hosts trailed 1-0 to the Republic of Ireland.
But a change in personnel and formation at the break proved to be a masterstroke, helping Les Bleus to come from behind and secure a convincing 2-1 win that will fill the squad with confidence going into a quarter-final against either England or Iceland in Paris next Sunday.
Deschamps has been rightly scrutinised for the apparent lack of a clear strategy so far at a European Championship his star-studded group are among the favourites to win.
But the coach of every major tournament's host nation faces an inherent challenge forging a cohesive team without the crucible of a qualification campaign in which to learn about his players and their responses to adversity.
For the former captain, the opening game against Romania was the first time Les Bleus had played competitively since exiting the World Cup to Germany in the quarter-finals on July 4, 2014.
Any advantage gleaned from having the entire country behind the squad - and the accompanying pressure makes that a double-edge sword - is surely negated by the unavoidable rustiness of more than a year of friendlies being the only opportunity to experiment.
So it has proved this month, when the most talented group of France players since the retirement of Zinedine Zidane have huffed and puffed their way through the group stage, rarely convincing and failing to harness the enormous potential they undeniably possess.
After late wins over Romania and Albania and a gritty, dour draw against Switzerland, which had relatively little riding on it, the first major moment of adversity for the team arrived within two minutes of kick-off at Stade de Lyon.
Paul Pogba's clumsy foul on Shane Long led to Robbie Brady scoring from the penalty spot, instantly raising the unthinkable prospect of the organisers being asked to leave their own party prematurely.
Stronger, more direct and more physically combative than any France's Group A opponents, the Republic of Ireland were always likely to be an awkward obstacle to negotiate, but going behind early on piled a deluge of unexpected additional pressure on the 11 men in blue and red.
Acknowledging his mistake in starting with a conservative 4-3-3 that failed to secure control of midfield, Deschamps then withdrew holder N'Golo Kante, who had been booked and will miss the last-eight clash at Stade de France, in favour of Kingsley Coman at half-time.
The 1998 World Cup and Euro 2000 winner Deschamps switched to 4-2-3-1, with Pogba and Blaise Matuidi sitting deepest and Dimitri Payet and Coman either side of Griezmann, who ran rampant after moving into a central role.
The Atletico Madrid player, who struggled in the first game but was the late hero against Albania, subsequently proved unstoppable, as the three men behind Olivier Giroud tore Ireland's defence apart with their movement and invention.
Coman in particular terrorised Stephen Ward, but it was Griezmann who claimed both goals - and it could have been more, as France dominated the final 30 minutes.
Tougher challenges will surely lie in wait and Deschamps is likely to retain justifiable concerns over his team's defence, Adil Rami in particular proving to be no substitute for the injured Raphael Varane.
But for now, Les Bleus can look ahead with optimism, having finally gone some way to satisfying the expectations of their demanding supporters with a second-half performance full of potential and menace.
