It might have been an ugly, scuffed shot that came off a shin, but it was also arguably the most beautiful moment in Welsh football history.
In the 81st minute, Hal Robson-Kanu snatched at a chance, from a piece of bad control from Aaron Ramsey, but he got just enough on the ball to give Wales a 2-1 lead.
They would hold on to it to secure their first-ever win at a European Championship, and their first at a major championships for 58 years since beating Hungary 2-1 at the 1958 World Cup finals.
Three hours later England drew their own opening game to leave Wales looking down on them, Russia and Slovakia from the top of Group B.
These are special days for Wales. The next five days, and quite likely beyond that, will see them camped out in the Promised Land.
It has taken 58 years, but at the moment, it seems it has been more than worth the wait.
Wales did not simply collect three points in Bordeaux; they comfortably won with a scintillating display of attacking football that will have their fans starting to believe.
Gareth Bale gave Wales the lead with a trademark free-kick, but when they allowed the Slovaks back in to the game with an equaliser in the second half, they didn’t meekly retreat and seek to protect a point; no, instead they charged forward to try to regain all three, which is an approach that will serve them well in tournament football.
Wales were always on the front foot. They played to win because this was the game they needed to win above all others.
The fixture-planners had been kind to the Welsh, giving them the weaker Slovaks to start, followed by England and Russia.
Wales have momentum now, but this victory also takes the pressure off them ahead of their game with England in Lens on Thursday afternoon, because they now know a win is not essential.
With four third-placed teams qualifying for the next round, this win makes it highly likely Wales will progress, and they know the addition of just one more point could confirm it.
Wales’s qualifying campaign was driven by the form of Gareth Bale, scorer of seven of their 11 goals, and the organisation of their defence. Here in France, these were again the twin pillars on which the Welsh performance was built.
Bale was in inspired form, constantly pushing Wales on; he wanted to be the man that made things happen all around him.
Inevitably it was his strike that gave Wales the lead in the first half, but he is one of 11 and can’t do it all.
Wales were solid, but not dull, organised, but never stifled, and they were able to attack with verve and fluidity because their defence continued to offer such a firm foundation.
During qualifying they only conceded four goals, and though they were breached once in Bordeaux, they largely quelled Slovakia.
The Wales manager Chris Coleman is a smart and underrated coach, enjoying this elevated platform to prove himself, and he devised plans to keep Wales on the attack in both halves.
In the first half he had his side, especially from the full-back positions, spraying long diagonal balls to open up the pitch, and use as much space as possible.
But in the second half when Slovakia closed them down on the flanks, they instead pushed through the middle, from where they scored the winner through the directness of Ramsey and Joe Ledley.
The winning goalscorer Robson-Kanu, and Ledley were both brave and attacking second-half substitutions by Coleman.
The selection of Jonny Williams to play in tandem up front with Bale was also another triumph for Coleman.
Despite being on the periphery at Crystal Palace, and cast out on loan at MK Dons and Nottingham Forest last season, Williams delivered a performance full of energy and intelligent movement and passing.
The criticism of Wales is they lack strength in depth, but here was Coleman shuffling his squad to great effect.
In the days leading up to Wales’ opening game Coleman had invoked the spirit of Denmark 1992 and Greece 2004, both small and unfashionable football nations who became European champions, and he tentatively compared his Wales side to them.
Even after banking three points so impressively against Slovakia, this is still dangerously premature talk, but Wales could certainly extend their stay in France for longer than expected, and England have been warned.