Mominul Haque surprised a lot of people today. Not because he batted like a dream, as Tamim Iqbal described it, or because he outpaced the more experienced Tamim in a defiant 157-run stand. The sense of surprise came from seeing him remain not out at the end of day's play, after having completed his second century in two Tests.
The records he has set by these back-to-back performances are numerous. A Bangladeshi batsman has hit two centuries in a series only once before, when Tamim had been in top form in England more than three years ago. Mominul also beat Tillakaratne Dilshan's tally of 366 to become the highest run-scorer in a series in Bangladesh and is four short of becoming the highest run-getter in a Test series by a Bangladeshi.
Mominul has been considered as one of the best cricketers in the country from his age-group, and not just for his talent but also for being a cool-headed, even-tempered person. It is a rare quality and although it doesn't guarantee success, he has remained almost the same person who was first spotted hitting Abdur Razzak for straight sixes two years ago in a practice match at this ground. He didn't look too flustered by the attention, just as he hadn't been when he was selected to the ODI side last year, his first international call-up, or when he scored his maiden Test century in Chittagong.
He had to be patient at a very young age too. Someone like Anamul Haque, two years younger to him in school (both went to BKSP), had hit the headlines for his string of centuries in age-group and domestic cricket. Mominul chipped away with runs, but never really caught the eye apart from one big innings for Bangladesh A in West Indies in 2011. He was never rushed in to the team like Anamul was, and that definitely helped him.
These two centuries have lit up his short Test career and there are a few similarities between them, while at the same time the adjustments he made when situations demanded them were refreshing to watch.
The 181 in Chittagong was an innings of two halves as he had to temper his strokeplay after completing a century. Despite walking in at 8 for 2, he blasted 70-odd in one evening session before hitting five boundaries to blaze to a hundred off 98 balls. It was a very Bangladeshi response to any situation, and there had to questions about his temperament for that change from his usual manner of batting.
New Zealand bowled better to him after the hundred, giving him very little to play outside the off stump. His favoured shots square of the wicket on the off side were nowhere to be seen but that didn't frustrate him. He let the likes of Shakib Al Hasan and Mushfiqur Rahim do most of the scoring, and made sure he dropped anchor.
Here at the Shere Bangla National Stadium, it was about survival from the get-go. He walked in at 55 for 2, with the team behind by 100 runs and in risk of conceding the series. Tight batting was required but there were moments, especially early on, when he played across the line as the left-arm seamers slanted the ball into him. It looked risky but the wrist work involved made sure he played the ball down, and a balanced head position helped too - benefits of extensive training over the last few months to counter his line of attack.
His off-side strokeplay, particularly shots off the back foot through point and gully, were fully controlled. His cover drives are struck in the air sometimes, but his skill in placing the ball saved him on most occasions. On the on side, Mominul picked up runs with ease, particularly off deliveries that were pitched up.
It wasn't an all-out attacking innings from Mominul, though. Tamim, his partner, had impressed the need for both of them to stay at the crease as long as possible and when Mominul was stuck on 99, unable to pierce a seven-two field on the off side, Tamim told him to forget about the hundred and just wait.
It arrived soon after, and like he did in Chittagong, the hundred was celebrated rather sedately. "Mominul has worked very hard and is getting the results," Tamim said. "I have seen very few players play so fluently for Bangladesh. Only when success comes to people they stray down the wrong path, they don't take that walk without success.
"But I don't think he is that type of person who cannot handle success; he doesn't think much about these things. I have seen a similarity in this respect between him and Shakib. Both have the same mentality. They also have the same coach. So I don't think he [Mominul] will have problems."
There will be a lot resting on Mominul going into the fifth day, especially with Bangladesh's batting not known for its survival skills. He will have to shoulder the expectations now and just like he shifted gears during his 181 in Chittagong, knuckle down and end New Zealand's chances of winning the game.

Mohammad Isam is ESPNcricinfo's Bangladesh correspondent. He tweets here