Please choose one:
Simple answer is they cracked under the pressure.
Ronaldo and Terry had way too much pressure. Ronaldo was thinking about his misses against Barca and in the league. Terry was thinking 'I am Mr Chelsea, I have wanted this for years' and as for Anelka he was thinking 'I am too lazy to take a proper run up and dont care if I miss as Im here for the money and cant believe my luck after being at a team in the bottom 3 in December'.
And yes I am able to mind read ala Matt Parkman. [;)][}:)]