UEFA referees' chief Pierluigi Collina has leapt to the defence of the additional assistant referee experiment after FIFA president Sepp Blatter declared Ukraine's European Championship defeat to England made goalline technology "a necessity".

The Euro 2012 co-hosts were denied an equaliser in Tuesday night's 1-0 Group D loss in Donetsk when officials failed to spot Marko Devic's shot cross the line. Blatter, who wants the International Football Association Board to give technology a go - posted on Twitter: "After last night's match £GLT is no longer an alternative but a necessity."

But Collina, once widely regarded as the world's best referee, said the mistake was the first failure in "thousands of matches" in which five officials had been used. "This is the only problem we have had," he said. "It's one negative decision in three years of Champions League and two years of Europa League and 24 matches in the Euro."

Tonight, Portugal face the Czech Republic in the first quarter-final of Euro 2012, with Cristiano Ronaldo's side favourites to claim victory.

Elsewhere, France are preparing for their clash against Spain amidst reports of in-fighting within the camp, whilst Italy are bracing themselves for a battle against England on Sunday night.

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