On a day when he impressed with bat, ball and as a captain, one moment captured Shakib Al Hasan's determination more than any other. His half-century had steadied Bangladesh after a troubled start, but they were still far from a safe score when he reached fifty in the 26th over. Shakib did not raise his bat to acknowledge the cheers for his landmark - here was a man who knew his job was not yet done.

"Well, I have said before that if the opportunity is there then one should target a hundred," Shakib said after the historic win. "Jamie [Siddons] also said that it is up to you whether you want to show the bat after a fifty. I was aware that I had reached the half-century but felt that there was a long way to go and my job wasn't finished."

Shakib's century was made special both by the quality of the opposition and the oppressive conditions in which it came. "Things were extremely tough because of the heat," Shakib said. "When I was batting I could feel that I was struggling physically and I still don't know how I got through those 50 overs of fielding and bowling because there were times when I thought I could collapse. I guess staying on the field for 50 overs was an achievement today."

His dismissal in the 43rd over set Bangladesh back, and they managed only 25 runs after his exit. Yet, Shakib said he was confident during the break that his bowlers had enough to defend. "I think we were set for 260 plus but lost it in the last Powerplay. However, I wasn't unhappy because we believe that we are capable of defending 240 on this track."

Bangladesh buzzed about in the field, putting up a memorable fielding show to down New Zealand, despite a valiant maiden ton from Kane Williamson. Shakib acknowledged the aggressive intent displayed on the field. "I feel privileged to be a part of this Bangladesh side. Today I saw players who would normally remain silent in the field shouting, cheering and encouraging throughout the game.

"Everyone was so into it, Imrul [Kayes], Suhrawadi [Shuvo] ... and I have lost count here. Even someone like Shafiul [Islam], who is relatively new in the side was all pumped up and shouting after bowling an over in that scorching heat. This is something that that I haven't seen often in the past and the spirit makes my job a lot easier."

The series win was Bangladesh's first against full-strength top opposition, but Shakib refused to rate it higher than the 3-0 win against a depleted West Indies side in 2009. "Many people don't realize this but the West Indies were not that far off from their original strength if you go by the players that had played against us. That was a tough series and this one too has been quite demanding. Both have been very satisfying."

Shakib has been a regular at the head of the ICC player ratings, and is currently the top ODI allrounder and the second highest-rated bowler in the game. However, he believed his bowling was far from where he wanted it to be. "I am quite happy with how I have batted in this series but not at all satisfied with my bowling. I guess the gap after playing for Worcester has affected the bowling a bit and I need to work on that."

While Bangladesh have managed to surprise each of the top teams at some point in the last 11 years, their lack of consistency has been a cause for concern. Shakib admitted that it would be his side's biggest challenge in the lead-up to the World Cup in the subcontinent.

"We were winning a lot of matches leading up to the 2007 World Cup and that had a positive impact on our performance in the tournament," Shakib said. "This time we are beating superior teams and I hope the winning trend will continue against Zimbabwe in December.

"If we can maintain that winning habit then we will be in a great state of mind when the World cup arrives and here we are a match for any team and capable of beating any side, particularly those that are not from the subcontinent."

The series may be in the bag, but Bangladesh have a lot at stake going into the dead rubber on Sunday. Victory will lift them to 67 rating points, level with the West Indies on the ICC one-day team ranking table. That should be motivation enough for Shakib and his side to deliver another inspired performance.