Jose Mourinho loves a challenge, and last night he was presented with two: playing the Champions League holders with 11 men, then doing so with 10. With a full complement he replicated the tactics which had been so successful in Milan, a 4-2-3-1 with a pair of holding midfielders and the wide men tracking Barcelona's full-backs.
Unlike in San Siro, Internazionale made no real attempt to get forward, content to sit back, allow Barcelona to pass in front of them, and seek to suffocate the hosts' threat when they approached goal.
For Barça Pep Guardiola made a subtle change in attack, moving Lionel Messi back to the right wing, swapping Pedro to the left, and giving Seydou Keita an old fashioned inside-left position inside Pedro and ahead of Xavi and Sergi Busquets. This left space behind Zlatan Ibrahimovic for Messi to drift into.
Guardiola also made changes at the back designed to counter Mourinho's tactics. Fielding Yaya Touré alongside Gerard Pique gave him two central defenders who could bring the ball out of defence. Deploying Gabriel Milito at left-back meant Samuel Eto'o, a centre-forward out of position, was marked by a centre-half out of position.
For 27 minutes Mourinho was the clear winner. Barcelona struggled to penetrate their opponents, failing to test Julio Cesar to any serious extent.
The dismissal of Thiago Motta changed everything and nothing. Inter were still sitting back. But their attacking threat was minimal. Christian Chivu dropped into Motta's position, Eto'o went wide left, Diego Milito wide right. Wesley Sneijder was nominally the lone forward, but the formation was in effect 4-2-3-0, moving to 4-1-4-0 when Barça advanced with Sneijder dropping in and Esteban Cambiasso holding.
Inter's expertise at playing when a man short (something Mourinho practises on the training field) was clear. Barça were too narrow. Guardiola sought to address this at the break, introducing Maxwell, but results were slow to arrive.
Further substitutes were added, and Barcelona finally attacked across the width of the pitch, but after Ibrahimovic was withdrawn none of their five most offensive players were taller than 5ft 9in which meant they had to either find the perfect cross, or go through the congested centre.
Guardiola was forced to resort to Sunday League tactics; stick the big man up front. Pique, however, proved more gifted a finisher than any parks player or many celebrated strikers. It was, however, too little, and too late.