Mushfiqur Rahim looked over his shoulder a couple of times at his batting partner Mahmudullah as they ran past each other three times. The Afghanistan fielders had bungled up a relay throw and then missed the back-up, allowing the three runs. Mushfiqur checked on his brother-in-law, who by now was limping visibly because of a calf injury.

Mahmudullah added to Bangladesh's approach of taking advantage of Afghanistan's sub-standard fielding. When they batted on the slow pitch of the Hampshire Bowl, one that offered turn and held back at times too, Bangladesh were surprisingly alert to every opportunity to pick up ones, twos and threes. It was a change of pace in their batting, as they looked to take advantage of every mistake Afghanistan made.

Their only problem seemed to be the spin trio of Rashid Khan, Mohammad Nabi and Mujeeb Ur Rahman, which isn't unexpected for any batting line-up. Keeping them at bay on a slow pitch must, perhaps, be Plan A for every team this World Cup. So like a tactically-sound team, Bangladesh not only planned rightfully, but executed them almost to perfection.

Mushfiqur struck only four fours and a six in his 83. He anchored the innings from the 18th to the penultimate over, with a change in his approach unlike how he had accelerated against Australia, who possess a stronger bowling attack although, on a flatter pitch.

WATCH on Hotstar (India only) - Mushfiqur's innings

Batsmen around him - like Shakib Al Hasan, Soumya Sarkar and Mahmudullah - also batted like Mushfiqur, hardly deviating from their set plan of not attacking the Afghanistan spinners.

They followed a similarly conservative approach while bowling. Bangladesh didn't bowl spin at all in the Powerplay, and then when they had extracted the sting out of Afghanistan's batting line-up in the middle overs, they again applied a safety-first approach. One can ask if they should have attacked at that point with enough space between the runs needed and balls to be bowled.

The only hitch in Bangladesh's approach was how they were rigid with their plans they had set even before the match started. They pushed Soumya Sarkar in the middle order so that he didn't have to face much of Mujeeb although the left-hand batsman doesn't have a known weakness against offspinners. Soumya, ironically, was later trapped lbw by Mujeeb without scoring a run off the six balls against the spinner.

Bangladesh's approach against the three spinners in the last 10 overs was also baffling. The plan was to shut them out as much as possible, so much so that they stopped looking for boundaries even off bad deliveries. It also affected how they approached the other bowlers. Bangladesh scored at just above six an over in the remaining 20 overs against Dawlat Zadran, Gulbadin Naib and Rahmat Shah. The pitch played a role too, and perhaps the combination of the pitch and the spinners strengthened their strategy.

But they had options to explore, particularly with wickets in hand in the last 15 overs. Perhaps two right-hand batsman could have been a bit more attacking against Nabi, a conventional offspinner who turns the ball into the batsmen. Mujeeb flighted the ball to Mushfiqur, who hardly brought out the slog-sweep, his pressure-releasing shot. Rashid was the best bowler on show, but the batsmen in the Bangladesh dressing room will exchange high-fives for keeping him wicketless and collecting over five an over off his 10 overs.

Numbers also reflected Bangladesh's approach, as their most twos and threes in this World Cup came against Afghanistan, as well as the least fours and sixes. As a result, the percentage of runs with boundaries was as low as 28.24. Incidentally, the last time they had taken more threes in a World Cup game was also against Afghanistan, in 2015.

Bangladesh tried to play like the bigger team in the park, doing the smaller things well - picking singles and twos whenever the chances arrived, and also being alert for overthrows. But they also had the option of tinkering with their overall strategy once the Afghanistan spinners stopped attacking the stumps. Instead, their default format was to second-guess the might of the spin trio.

These are conventional decision-making and strategies Bangladesh stuck to. As long as they want to remain a mid-table team in the long run, they are more likely to find success with this approach against Afghanistan or other lower-ranked teams. But if their ambition is to be a top side, even in this World Cup, they have to press the accelerator harder at times.

Ultimately, not giving Rashid, Nabi and Mujeeb the control mattered, and their approach on a slow pitch would have been satisfying. But in a tournament where they are trying to tell the world that they are among the big guns, they should also start adding ruthlessness to their system.

Bangladesh bossed Afghanistan. But in a nice way.

Mohammad Isam is ESPNcricinfo's Bangladesh correspondent. @isam84