Some almost comical fielding, not to mention hilarious batting mix-ups, could not disguise the very serious threat Pakistan are starting to pose at the World Cup after silencing a Sri Lankan crowd on Saturday.

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In their skipper Shahid Afridi, the Pakistan attack has a potent weapon which proved just as deadly to Sri Lanka's classy batting line-up as it did to the less gifted Kenyans.

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This time the leg spinner grabbed four valuable wickets (4-34) to stop Sri Lanka in their tracks and set the scene for a fairly comfortable 11-run victory, Pakistan having made 277-7 batting first with Misbah-ul-Haq unbeaten on 83 and Younus Khan 72.

The result leaves Afridi's men in the driving seat in Group A and sitting pretty already for a quarter-final berth in late March.

Sri Lanka, meanwhile, will not be able to afford too many more slip-ups following this disappointing performance after making the costly decision to give their main strike bowler Lasith Malinga more time to recover from a sore back.

Yet there was plenty to criticise in this Pakistan performance, as man-of-the-match Afridi himself conceded later.

The batting run-out in which Mohammad Hafeez (32) lost his wicket was a cricketing tragicomedy as both he and his partner Kamran Akmal (39) found themselves miserably stranded at the wrong end before briefly looking dumbfounded as to which of them had to go.

Equally, Pakistan's fielders dropped a couple of sitters in the field as the pressure began to build late in the Sri Lanka innings and wicketkeeper Kamran Akmal managed to blow at least one clear stumping chance.

But any opponent at this World Cup thinking that Pakistan are not deadly earnest in adding to their sole World Cup title of 1992 would be making a big error.

The team under the intensely focused Afridi has plenty of talent with bat and ball and a nice balance with both.

Afridi believes that it was a laid-back attitude rather than a big occasion in front of a deeply partisan, capacity Colombo crowd willing them to lose which made their cricket a little ragged on occasion.

"It was a big game and the boys all knew how big the game was. The boys were a little too relaxed and we need to tell them on this kind of stage they should not relax," he said.

"It's beautiful conditions, especially for bowlers. The wicket gives you turn and bounce as well, so it also helps the fast bowlers if they keep their line."

His opposite number, Kumar Sangakkara, tried to look on the bright side.

"Any defeat is tough but quite a few positives to take. I thought we bowled pretty well on a pretty flat track. Unfortunately, we lost three wickets at the wrong time," he said.

"We made it a bit difficult for ourselves by losing wickets. We got a good start, we needed a couple of blokes to kick on from there and keep batting for a longer time. Unfortunately, Pakistan played very well."

They certainly did despite the blemishes and this victory should not be under-estimated against a team which has its own very strong credentials to repeat its triumph in the tournament 15 years ago.

Pakistan won the toss and made steady progress to reach 105-3 whereupon Younus and Misbah took control of a fairly toothless Sri Lankan attack which badly missed Malinga.

They put on 108 for the fourth wicket and their eventual total of 277 at 5.54 runs an over represented about par for the course on a wicket which was getting slower and slower as the day/night match wore on.

In response, Upul Tharanga (33) and Tillakaratne Dilshan (41) progressed through the early overs with no real problems before Tharanga failed to get over a full delivery from Hafeez and was well caught at extra cover by the ubiquitous Afridi.

There then followed a mini implosion with the next three wickets falling for a total of just 20 more runs leaving Sri Lanka in serious trouble at 96-4.

Chamara Silva (57) and Angelo Mathews (18) steadied the ship but in adding 73 runs for the fifth wicket in 16.2 overs, they left their team well behind the run rate.

A late flourish from Nuwan Kulasekara (24 off 14 balls) coupled with some frankly sloppy bowling from Shoaib Akhtar (2-42) and Umur Gul (1-60) gave the home side a sliver of a chance but when Kulasekara was out caught in the deep the game was up.

Pakistan already deserve a lot of credit at this World Cup.

They have played some terrific cricket in gaining two impressive wins and are making good Afridi's promise that they will put behind them all their pre-World Cup woes including the ongoing corruption case against three of their former team mates, Salman Butt, Mohammad Amir and Mohammad Asif.

Whatever the merits of their case, their former team mates are clearly focusing very much on the field and when this Pakistan side does that, they can be very hard to beat.