The coaches of Uruguay and Ghana have brushed aside conspiracy theories claiming Howard Webb was replaced as the referee in charge of tomorrow's World Cup quarter-final between the sides because of the controversy over Frank Lampard's disallowed goal against Germany.

A Uruguayan referee team, led by Jorge Larrionda, was in charge of the England's 4-1 thrashing to Joachim Löw's side last Sunday, when Lampard's shot clearly crossed the line but no goal was given.

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Fifa announced today that the Portuguese official Olegário Benquerenca will take charge of the Uruguay v Ghana game in Cape Town and said there was no question that Webb, who has not been given a last-eight match, had originally been earmarked for the match.

The Uruguay coach Oscar Tabárez said: "It seems every time there is a slight coincidence of any sort we start to dramatise things. We have nothing to do with refereeing – they are like a player and they can do well or do badly, we don't have any suspicions, it does not exist as far as we are concerned.

The Ghana coach Milovan Rajevac said: "I pay no attention to who will be our referee – it's the highest level of competition and the referee will be of the highest level. After a match I never make comments about the referee so I'm not even thinking about it."

Uruguay qualified for the finals via a play-off but have been one of the surprises of the tournament under their vastly experienced 63-year-old coach. Reaching the semi-finals would be the best achievement by the first winners of the World Cup – Uruguay triumphed in 1930 and 1950 – since 1970, but Tabárez has warned against looking back at past glories.

"I don't want to look back and talk about the historical dimension – anything that involves thinking beyond tomorrow makes us lose concentration," he said. "Perhaps later on we will be able to talk about the historical significance. First we have to play this quarter-final against Ghana and they are very strong, with very fast players with good dribbling skills."