Powell's side stormed into the Olympic quarter-finals by beating Brazil at Wembley.
There have been more significant achievements but even Football Association officials privately conceded that against such formidable opposition, in front of a British record 70,584 crowd, there has been no better evening.
In pure statistical terms, Houghton's third goal of the tournament meant Kelly Smith could afford to miss a second-half penalty and GB still managed to avoid a last eight meeting with World Cup winners Japan.
Instead they must play Canada, no slouches themselves as the seventh-ranked nation in the world, in Coventry on Friday.
But after years of railing at the lack of attention given to women's football, Powell's women had the chance to take centre stage. And just as she promised, the walked right into the spotlight.
Great Britain should not be confused with England.
The presence of Kim Little in Powell's starting line-up and the now injured Ifeoma Dieke in her original squad was confirmation enough of Scottish representation.
Yet a measure of the task GB faced was the knowledge that England had beaten Brazil, in a competitive match, at any age group, by either gender, just once.
It came in the Under-17s World Cup in 2007. The most notable members of the victorious team were Danny Welbeck, Victor Moses and Henri Lansbury.
Though the crowd was big, and noisy, few expected Britain to make a mockery of that statistic.
Unbelievably, within two minute, they were in front.
Struggling to clear an early corner, Brazil's lethargic defence allowed Karen Carney to chase down a loose ball, turn and then thread a pass through a posse of opposition players.
Houghton read it brilliantly, nipped past Andreia and from the tightest of angles, rolled in.
It was Houghton's third goal of the competition and the noise that greeted it was amazing.
On the touchline, Powell's first reaction was telling. Hands down. Calm down.
For the only problem with the goal was the finishing line being almost an entire match away. And Brazil, being Brazil, have players who can hurt.
Renata Costa belted a long-range free-kick over, Karen Bardsley denied Cristiane, then skipper Marta, both players Powell highlighted as obvious dangers 24 hours earlier.
GB tried to release the pressure but it was the second-half before they created chances of their own. And they have three good ones, within 10 minutes of the restart.
Unmarked, in a central position, Little should have scored with a firm header which went straight to Andreia.
Then Eniola Aluko found a bit of space on the right of the area, only to slash her shot wide.
When Aluko was tripped by Francielle, Kelly Smith had the responsibility of converting from the spot. But the pressure was too great and a poor spot-kick was turned away by Andreia.
Against opposition of such strength, moments like that can often be pivotal.
And a previously becalmed Brazil were reignited as a result.
But Bardsley was equally inspired, turning away an ambitious effort from Marta with her feet.
When two more promising attacks came to nothing, it seemed to sap the strength out of Brazilian legs.
It only left GB to hold their nerve and run the clock down.
Powell sensed it and introduced Ellen White to do a bit of extra running up front.
It worked a treat. And the jubilation at the end, on and off the pitch, was a sight to behold.