From TheChels.info - The Chelsea Football Club Wiki
To the tune of "Amore".
When the ball hits the back of the Old Trafford net, it's1 Vialli,
When his goals light the sky there's a tear in my eye, oh Vialli!
Alternative second line:
He nutmegged the Dane and poor Fergie's in pain, it's Vialli!
1 Alternatively, "that's Vialli"