Shakib Al Hasan's last ball of the spell had him trying to hit Colin de Grandhomme's front pad. He delivered the ball, and then spun around in anguish as he saw the batsman connect with it properly. It was close to his pads, but not quite. It ended a superb spell of bowling - 10-0-47-2 - on a flat pitch that had nothing for a spinner even of his quality.

When Mohammad Saifuddin conceded the boundary that tied the scores in the 47th over, he too turned around slowly and took his cap from the umpire. He had taken two wickets from seven overs, but it wasn't enough. Saifuddin has a lot left to acquire as a seamer, so now he is all heart, trying to force the ball past the batsman, or trying to hit the stumps.

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Bangladesh tried to defend their 244-run total admirably in front of a sellout crowd at The Oval, but they fell short by two wickets. In real world terms, they were certainly short by 40 runs against a New Zealand batting line-up that had dominated them earlier in the year. But when they got the game close, they would have expected to close it down too with penetration from both ends.

Bangladesh's bowling attack, despite their talent, skills and fighting ability that has served the team well in the last four years, doesn't always have the killer blow. In a World Cup game when they tried to defend a middling total, they didn't land enough of those blows. Mustafizur Rahman is their strike bowler while Shakib, despite his superb effort with the ball, can be expected to keep one end tied up. But he does a lot more, as he is often their main wicket-taker.

Captain Mashrafe Mortaza has also done surprisingly well in the last four years despite so many injuries and modifications in his run-up, speeds and action. Saifuddin and Mehidy Hasan are trusted with different duties in specific phases of the innings, much of which they do quite well.

But the bowling attack needs wicket-takers.

Take for example the first Powerplay. Mashrafe used four bowlers, including himself. Shakib, brought into the attack in the fifth over, took a wicket with his first ball. Colin Munro became his second wicket in the tenth over, but Shakib was kept on until the 18th over. Shakib kept New Zealand under pressure from one end. In the 12th over, bowled by Shakib, three chances were created. Two of them were run-out opportunities while Ross Taylor nearly dragged an arm-ball onto his stumps.

But Mashrafe's reliance was a clear message that there was a lack of wicket-taking options in his bowling attack. Since he decided to use Mustafizur for just one over till Shakib finished his first spell, he needed Shakib for both cutting out the runs and finding a wicket. For a left-arm spinner, the latter becomes difficult on an unresponsive surface.

The same is true of medium-pacers like Mashrafe and Saifuddin, as well as offspinners Mehidy and Mosaddek Hossain. They are all effective in home conditions, and that has given them so many wins and put them in the winning mindset in this World Cup. There is no denying that the Bangladesh line-up have good bowlers who have been as much part of their progress for the past four years, as their batsmen. The fact that Mashrafe can regularly call upon a three-man, and sometimes a four-man pace attack, is a sign of how far they have come as a bowling unit. Spin has been the staple at home where they take advantage of the lack of pace and bounce in pitches in Dhaka and Chittagong.

They are accurate in overseas conditions, as was evident during their tri-series win in Ireland where Mehidy and Shakib slowed down West Indies after they had made quick starts. But perhaps that's as good as one can expect them to do in these conditions.

In a World Cup field where there are nine different challenges, Bangladesh will struggle with one strike bowler in Mustafizur, and Shakib trying to play many roles at once. Others need to step up, and become wicket-takers.

Bangladesh found out the difference between defending a middling total in Mirpur and defending one at the World Cup in England. The good news is that the first major lesson has come in the second game itself, which means they have enough time to understand what is needed in different phases of the innings.

First and foremost in that list, as far as bowling is concerned, is certainly the ability to pick up wickets when the opposition is building a partnership, which can take the game away from them despite late wickets.

Mohammad Isam is ESPNcricinfo's Bangladesh correspondent. @isam84