New Delhi: Cricket is just a game, but try telling that to the 22 players who will walk out for the India v Pakistan World Cup match in Adelaide on Feb 15.

The Pool B contest was sold out in 20 minutes and no other team in world sport will be under as much pressure as the two that day with 1.3 billion unforgiving cricket-crazy fans following the contest ball by ball.

Emotions run high every time the south Asian neighbours, who have fought three wars since independence and share frosty relations over the Kashmir region they both claim, clash on a cricket ground.

Pakistan, champions in 1992, have never beaten twice winners India at a World Cup.

Many of their fans would not mind their team crashing out from the World Cup early, providing they beat their neighbours. The rivalry assuming the Orwellian concept of serious sport - war minus shooting.

"For many, it's bigger than World Cup," former Pakistan speedster Shoaib Akhtar told a cricket conclave in Delhi on Monday.

"It completely locks out 1.3 billion people. The tension is unbearable and the players' effort level doubles. We could never beat India in World Cup but, God willing, that would soon happen," said the quick known as the 'Rawalpindi Express'.

A veteran of many such contests, Harbhajan Singh was part of the eventual champion Indian team who beat Pakistan in the 2011 semi-final at Mohali, a contest that gave him sleepless nights.

"The dressing room atmosphere is always tense," said the feisty off-spinner who could not make the cut for this year's World Cup.

"Much before the dressing room, you think about it in your hotel room. Before last World Cup's match in Mohali, I could not sleep the night before, thinking what if we lose.

"Fortunately we won the next day and again I could not sleep, this time because I was so overjoyed.

"A defeat against Pakistan means media would roast us and fans would pelt stones at our house," said the 34-year-old.

His team mate from the 2011 squad, Piyush Chawla, said the pressure does not come from the team management.

"It comes from elsewhere. Even family members and friends remind us it's a match against Pakistan," said the 26-year-old leg-spinner.

"Fielding in the deep, you often hear the crowd behind warning you 'better win this match or it won't be easy to get out of the stadium'."