The defender thought he'd done his job, intercepting the pass, putting his body between the ball and the attacker. But a couple of seconds later, in a sudden flurry of elbows and knees, accompanied by that strangely harsh susurration, Hristo Stoichkov was in front of him, stealing the ball and moving away.
In a stadium, that swift noise - the unexpected soundtrack to the eruption of Stoichkov's darkly menacing presence - would be lost amidst the hubbub. Here, on Thursday morning, only a couple of hundred schoolchildren watched as the Bulgarian forward and the rest of the Barcelona first-team squad went through their routines on the practice pitch next to the massive Camp Nou.
It was reassuring to discover that Stoichkov is no more a little ray of sunshine in a four-a-side exercise than he is in front of a packed house. He brooded, he glowered, he ran the gamut of sulks. But he also showed, in his explosive sprints and fulminating shots, why Barcelona's coach, Johan Cruyff, is so keen to keep him motivated as the season approaches its climax.
Cruyff, still whippet-thin as he approaches 50, bound to Barcelona first as a player, then as a coach, and more recently by ties of blood (his son Jordi is in the first-team squad, and one of his daughters is married to the third-choice goalkeeper), watched thoughtfully as Stoichkov went through his repertoire. Of all his expensive collection of players, the Bulgarian is probably the one on whom the team's immediate fortunes depend, starting this week. And after a series of mid- season spats, the two have returned to something like a cordial relationship in time for what promises to be a testing climax to the season for a football club that can legitimately claim, on its basis of its 100,000-plus season ticket holders, to be the world's greatest.
Yet Barcelona, in common with Bayern Munich, Manchester United, Milan and Paris St-Germain, have found it hard to maintain their domestic pre- eminence this season. And all of them, apart from the Old Trafford club, are still in the European Cup, which resumes on Wednesday evening with the first leg of the quarter-finals. Today Cruyff begins his preparation for the visit of Paris Saint-Germain - managed by Luis Fernandez, the former French midfield player, whose hero-worship of the Dutch genius is such that his nine-year-old son is named Johan.
Cruyff sent one of his lieutenants to watch PSG beat Lyons in the French league last week, but he was not interested in discussing his next date in Europe. His mind, he claimed, was completely occupied with the challenge presented by Santiago de Compostela, this weekend's opponents in the Spanish league, which Cruyff is still hoping to win for the fifth consecutive season.
With 16 matches left, Barcelona started the weekend five points behind Real Madrid, their bitterest rivals, whose self-confidence has been restored by a new coach, the former Argentinian international Jorge Valdano. Barca's response has been erratic, the team that beat Manchester United 4-0 with a dazzling performance in the Camp Nou also managing to lose 5-0 away both to Real and to the lowly Racing Club de Santander. Cruyff, however, is not giving up hope. "It'll be hard, but it's possible," he said. "And it doesn't only depend on us. Real will have to drop points."
He was thinking of last year, when Barcelona won the title on the final day thanks to someone else's failure. When Miroslav Djukic of Deportivo la Corua saw his 88th- minute penalty saved by the Valencia goalkeeper while Barcelona were beating Seville 5-2, it was the conclusion of a decline that had seen Deportivo fritter away a seven-point lead.
The price of Barcelona's euphoria was paid in full a mere four days later when they went to Athens to meet Milan in the final of the 1994 European Cup and were thrashed 4-0, traumatising the team and their 30,000 travelling supporters.
Had Cruyff sat down afterwards and analysed the defeat? "I think it was quite clear," he told me. "We'd just won the league, and the atmosphere here was . . . well, it was like a bottle of mineral water. You shake it, you take off the top, it bubbles, and then it's gone. By the time we got to Athens, we could have been playing against any team and we still wouldn't have won. It didn't have to be Milan."
Over-commitment has been behind the problems experienced by many of the big clubs this season, he thinks. "We have 14 players who were in the World Cup. Each of them only has one body. They're not supermen. If you see the list of injuries, it's ridiculous. If you only get two weeks' holiday in a season when you have to play about 70 official games, that's what's going to happen. I've said it before: our biggest opponents are the national federations, and Uefa and Fifa. They don't understand the problem because they don't play the game."
One man who extended his two-week holiday after the World Cup was Romario, celebrating long and hard at home in Brazil before returning to Barcelona, where Cruyff greeted him with a fine and extra time in the gym. Four league goals before Christmas were not enough to rekindle the coach's warm feelings, and Romario returned to Rio de Janeiro, sold to Flamengo for £2m with 18 months of his three-year contract left.
Bobby Robson, who coached Romario at PSV Eindhoven, once described the Brazilian as the most difficult player he'd ever had to handle. Now that Cruyff had got rid of him, would he agree? "He wasn't easy. He is a good player, especially last year. But we had him when he was positive, and we sent him away when he was negative."
Had he changed Barca's tactical approach to compensate for the absence of the World Cup's individual star? "No. The adjustments haven't been great, because he didn't really influence the collective way we play. He was the end product, not really part of the system."
Still, the rumours grow that Cruyff plans to buy a big-name replacement this summer. The favourite is Dennis Bergkamp, his old Ajax protg, languishing in his second disastrous year at Internazionale, whose new president, Massimo Moratti, said last week: "Dennis hasn't done anything since he's been here. He seems to want to play for Cruyff at Barcelona. That's fine. We'll swap him for Stoichkov."
Such an exchange would provoke an uprising in the Camp Nou, where Stoichkov is revered with a fervour that Romario never evoked. But a straight purchase might not be out of the question. Publicly, Bergkamp has been insisting that he still wants to make a go of it in Milan, and Cruyff was deflecting last week's inquiries with enigmatic comments. "We're not interested in the way he is now as a player," he said, which seemed to leave plenty of room for manoeuvre.
We shall see. Meanwhile, would Cruyff buy Eric Cantona as Romario's replacement?
But he did have admiring words last week for Roberto Baggio, who is slowly recovering from injury and may be tempted away from Italy this summer if Juventus fail to qualify for the European Cup by winning the Italian league, which they currently lead. Cruyff told an audience of children at Barcelona's soccer school on Thursday that Baggio was one of the three foreign players he most enjoyed watching at the moment, the others being Aron Winter and Ryan Giggs.
Cruyff's recent record in the transfer market has not been good. In the summer, to the sorrow of the fans, he sold Michael Laudrup, only to see the Dane inspire Real Madrid's renaissance. To replace Laudrup he decided against Rui Costa, the Portuguese midfielder who went instead to Fiorentina and is doing well, and bought Gheorghe Hagi, the unpredictable Romanian. The £2m fee for Hagi took Cruyff's spending in seven years at Barcelona to £31m, against £20m accruing from his outward transactions. But the World Cup had taken the steam out of Hagi, whose appearances in Barca's shimmering blue and red shirts have been limited by injury.
"He needed time to recuperate after the mental and physical pressures of last summer," Cruyff said, with a hint of exasperation.
And how is his general level of fitness now?
"Well, I can't be satisfied with someone who can only play in half our games."
Is he keeping his weight down?
"He's out for another month with a knee injury, so I don't care what his weight is."
So did he have any regrets about exchanging Hagi for Laudrup?
"No. Not at all."
Market forces tell their own story, however, and in the souvenir shops lining the Ramblas the replica Barca shirts bearing Laudrup's name far outnumber those carrying Hagi's.
But waste no tears on FC Barcelona. By any yardstick, Real Madrid, £30m in debt, have far greater need of this year's Spanish title. And Cruyff is still guiding his team towards a May rendezvous in Vienna with Ajax, a potential meeting of satisfying contrasts - age versus youth, big spending versus frugality - that in personal terms would provide yet another climax to a career rich in passion and reward.
For that to happen, however, a few more defenders will first have to feel the hot breath of Hristo Stoichkov on their necks, and hear the sound of ripping silk.