On the Portuguese night in March 1966 when a Manchester United side were sent out for the match against Benfica which was to define George Best's talent like few others, Sir Matt Busby told them to keep things tight. Within 12 minutes Best had scored twice, his header and slalom run past three defenders setting up the 5-1 win for the side who became "the lions of Lisbon". A few hours later, Busby turned to Best and said, "You obviously weren't listening".
The scene was set for something remarkably similar last night when, two minutes after Sir Alex Ferguson had sent his side out, presumably with the same message about containment he had been preaching all week, the world prepared to learn something about Cristiano Ronaldo and about the comparisons with Best.
A penalty-kick, two minutes into a Champions League semi-final, with the whistles of a 98,000 capacity crowd ringing in his ears? It was something for which the hours he has spent learning of United's rich European history on the club's TV channel could not have begun to equip him. Ronaldo tends to blast his penalties low but a change of tack was imperious. But when he half chipped, half kicked the ball into one of the green stanchions, yards wide and high of Victor Valdes' left post, he brought the sense of his own development into sharper context.
A single kick cannot define a player's contribution. It was how Ronaldo might respond to it which would be the mark of whether he has grown since the semi-final defeat in Milan last May, for which Ferguson has admitted that his young players were "not ready".
Ronaldo did not shrink into a shell after standing, face in hands, on the penalty spot. The juggles before he played a dead ball back to Gianluca Zambrotta, the verbal altercation with Valdes who had clipped him as he collected a ball placed out of the winger's reach by Michael Carrick, the deep inhalation before a free-kick he won 20 yards out – all were signs of the showman Ronaldo will always be.
But this was a night which made the Best comparisons short-lived. A more abiding image will be of the Portugal international on the right flank, arms thrown out ahead, in frustration at a free-kick refused after Zambrotta had put a stop to a run early in the second half.
This match was, Barcelona's Lionel Messi had insisted, "not a game between Cristiano and me". But though Messi departed after little more than an hour, his contribution threw Ronaldo's into contrast. It was as much an appointment with history for Messi as Ronaldo; as much a test of whether the Argentine could dominate the big stage. For Messi, the concerns are physical. He wept when he hobbled out of his last Champions League game with a recurrence of the thigh problem that may be the result of a childhood hormone deficiency.
His unkempt hair and shuffling walk are as far from Ronaldo's gel and confident stride as you'll get. But it was Messi who most proved his worth. His angular reverse pass beyond Wes Brown which allowed Andres Iniesta to skip past Owen Hargreaves and cross low from the left was a threat of things to come.
When Paul Scholes and Michael Carrick conspired to stunt his runs, Messi worked his way sideways and delivered to Eric Abidal to cross from the left. He glided past Patrice Evra and Park Ji Sung in turn, a juggle and flick over Evra's head and control on his thigh proving theirs was a match of unequals. The exquisite interchange of passes between Messi and Iniesta which sent Samuel Eto'o in, in the second half, was, as Ferguson observed, Barcelona's clearest chance.
Ronaldo remains top of the Champions League scorers chart, a goal ahead of Messi by dint of the Argentine's injury. But as Barcelona's finest exited to the roar of "Messi", who left the stadium with an ice pack around his thigh, it was clear who has most to prove on the grandest stage.