England batsman Kevin Pietersen believes Sri Lanka spinner Muttiah Muralitharan is the best bowler in the world and harder to face than Australian great Shane Warne.

Pietersen, the world's top ranked one-day batsman, will face off-spinner Muralitharan on Wednesday when England clash with Sri Lanka in a World Cup Super Eights match in Antigua.

"Muralitharan is the hardest bowler in the world to face," Pietersen told reporters on Monday. "Much harder [than Warne]. He is a true great of the game.

"Murali spins the ball both ways whereas Warney you can sort of counteract."

Warne, who retired after Australia's 5-0 Ashes test whitewash over England in January, was known for his sledging but Pietersen said Muralitharan lets his bowling do the talking.

"Muralitharan just winds you up because he knows he is going to get you out. He just smiles and laughs. 'Silent assassin' I call him.

EASILY SURPASS

"He has so much talk with the cricket ball he doesn't have to say much," added Pietersen, who plays with Warne at English county side Hampshire and was good friends with him before a spat during the Ashes.

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Warne holds the record for the most Test wickets but Muralitharan, who has 674 victims, will easily surpass Warne's total of 708.

Pietersen said England had to win against Sri Lanka or world champions Australia on Sunday to have a realistic chance of reaching the semi-finals.

They have two points following Friday's win over Ireland and move on to Barbados for the rest of the Super Eights after the Australia clash.

"We haven't reached top gear, Wednesday the World Cup starts for England," the South-African born batsman said. "It's a huge week for us. We can't leave Antigua on Monday with just two points. It'll be a great batting line-up when it's firing."