A linesman's flag in the 12th minute denied Thierry Henry an early chance to inscribe his autograph across last night's Champions League semi-final, an event on which his future at Arsenal may depend.

It was a tight call, and replays suggested the official got it wrong, perhaps confused by another redcurrant shirt in a passive offside position just beyond Henry as Robert Pires threaded an exquisite pass to his captain.

Henry, making his stealthy advance down the inside-left channel, finished in the most clinical manner possible, opening his body and steering the ball with the inside of his right boot past Mariano Barbosa's left hand. It was the perfect Henry goal, the product of speed, timing and precision, but it was not to stand.

This was, nevertheless, a night built for English football's biggest star. After Ronaldinho's moments of magic at San Siro the previous evening, all Europe waited to see what Henry had to offer in response, counting its blessings that the continent's leading club competition is once again providing a setting for such sublimely gifted performers.

The shadows of Di Stefano, Kopa, Puskas, Eusebio, Rivera and Best flickered in the background as the Brazilian and the Frenchman took advantage of the floodlit stage, two right-footed players working the left-side channels and wreaking havoc on the mental and physical equilibrium of a generation of celebrated defenders.

Where Ronaldinho smiles, Henry shrugs. But it is the shrug of a man who is saying, well, that might not have come off, but just wait.

He would have been delighted with the way his colleagues began last night's match. The youngsters and veterans alike were all pace and movement, with the junior defenders in particular showing initiative and a complete lack of anxiety as they launched their attacks.

Henry's first significant contribution came after three minutes, when he dinked a free-kick gently from the left, its cunning arc and inswing bamboozling the Villarreal defence and falling just behind Kolo Toure, who turned and scuffed his shot wide. Four minutes later his corner from the left found the head of Gilberto Silva, who steered the ball across the goal but wide of the post.

The disallowed goal signalled the end of Arsenal's early dominance. Instead of a relentless acceleration through the gears, suddenly they were finding only neutral as, for the first time, the Yellow Submarine began to make headway. When the rat-tat-tat of first-time passes turns into a fragmented tattoo, the risks inherent in Wenger's total commitment to a high-tempo game become visible, and Juan Roman Riquelme, piloting the Spanish advances, is just the sort of player capable of taking advantage of a momentary change of mood and rhythm.

Henry brought Arsenal to life again in the 10 minutes before half-time, skimming past Javi Venta down the left and firing over a firm cross that pinballed around the area before bouncing to safety. Four minutes before the interval he did the same again, this time winning a corner after good work from Pires and Freddie Ljungberg. He took the flag-kick himself, of course, and collected the headed clearance, finding Alexander Hleb with a wonderfully sudden reverse-angle pass and then stood back to watch in satisfaction as Toure forced in Hleb's centre.

Henry expressed irritation before the match at the constant questions about his intentions this summer. Arsenal's ultimate fate in the Champions League will probably have a bearing on his decision. Last night, however, he played as though there was only one thing on his mind.