|1||Van der Sar|
Ronaldinho put the Rossoneri ahead inside three minutes and the hosts spurned several opportunities to further their advantage before Paul Scholes' fortunate leveller 10 minutes before half-time. The Reds dominated midfield after the break, however, and two headers from Wayne Rooney gave Sir Alex Ferguson's side two more priceless away goals.
Clarence Seedorf impishly back-heeled the hosts back into the tie and Michael Carrick was dismissed for a second booking as Milan finished strongly, but United's first ever victory at the San Siro gives the Reds a vital lead ahead of the second leg at Old Trafford.
Much of the pre-match fanfare centred around David Beckham's first clash with United since leaving Old Trafford in 2003. In truth, it was Ronaldinho, the man unsuccessfully earmarked to replace Beckham, who had the greater influence for Leonardo's side.
United could hardly have made a worse start. Just over two minutes had passed when Patrice Evra's attempt to clear Beckham's free-kick only went as far as Ronaldinho, and the Brazilian's right-footed volley took a telling deflection off Carrick and flew past the committed Edwin van der Sar.
The Reds were rocked, while Milan were galvanised into dominance. Ronaldinho, clearly relishing the occasion, drew a smart stop from van der Sar with another close-range effort as the hosts aimed to forge a greater advantage.