Inter Milan coach Jose Mourinho says zonal marking was the key as his side stopped Lionel Messi.
Messi had scored 29 goals in his previous 29 matches prior to Wednesday and the Argentina winger's breathtaking form this season has led to many hailing him as the world's greatest ever player, all at the tender age of 22.
But Messi had faced Mourinho sides on six previous occasions and failed to score in any of those matches.
And six became seven as 10-man Inter defended with both heroism and cynicism to deny the fleet-footed Argentinian and secure passage to next month's Champions League final in Madrid following a 1-0 defeat at the Nou Camp.
Above all, though, Mourinho's negation of Messi owed more to order and organisation, the Portuguese coach said.
"I am against man-to-man marking," he said.
"We defend as a team, in zones - one man alone cannot stop Messi.
"You can't say it was (Esteban) Cambiasso that stopped Messi or that our midfield or our defence stopped Messi - we worked together and playing in zones.
"Everyone knows their positions and we defended exceptionally."
Following Barcelona's surprise 3-1 first-leg defeat in Milan last week, an Italian journalist asked coach Pep Guardiola what had been wrong with Lionel Messi.
"Come to Barcelona and you'll see what Messi is all about," Guardiola replied.
But the Barca coach was forced to admit that his player had struggled at the Nou Camp, starved for space by Inter's no-nonsense back-line.
"It was difficult for him because there was hardly any space between the midfield and the defence and he couldn't play as he usually does," Guardiola said.
Chelsea had used the same tactic to great effect last season, despite ultimately losing out in dramatic circumstances in the Champions League semi-finals, and Espanyol almost beat Barca two weeks ago by employing a similar ultra-defensive system.
Nevertheless, a surprisingly upbeat Guardiola denied that Barca are being found out.
"We have lost nine games in two years and we'll continue to be ourselves - tonight we gave everything but it wasn't enough.
"We won't change the way we play, though, and anyway, it has brought a lot of success," he said.
That said, Mourinho's blueprint for halting Messi will have been noted by teams across Spain and Europe.
Nevertheless, Inter striker Samuel Eto'o believes his former side remain the best in the world.
"They are still the best side in the world, but they can lose two or three games, which is what happened here," he said.
"We defended the best we could and used our qualities to stop this marvellous team, which is the best in the world."
Those qualities, as well as some new-found belief that they can beat the best, have been instilled by Mourinho.
The Portuguese had arrived in Barcelona flanked by two burly bodyguards, but claimed he did not need them.
Stopping Messi, though, was something he was unable to do alone.
"You have played against Messi six times..." a journalist said to Mourinho on Tuesday.
The coach interrupted: "Me? If I played against Messi, I would lose 50-0 and I wouldn't touch the ball."
But little over 24 hours later, and thanks to more than a little help from his defenders, the joke was on Barca.
"We didn't want the ball because we didn't want to lose our positions, so we gifted them possession," he said.
"Playing with order, and without the ball, we have shown that it is possible to stop the best team in the world."
