Less than 45 days out from the T20 World Cup, Bangladesh are walking a tightrope between whipping up a winning feeling and experiencing a slump in their batters' confidence, with the pitches at the Shere Bangla National Stadium in Dhaka at the centre of this conundrum. The surfaces haven't come together well; they have lacked pace and produced sharp spin and uneven bounce. It's unlikely Bangladesh will play on similar tracks in Oman and the UAE when the T20 World Cup gets underway on October 17.

Teams batting first in Dhaka have averaged 117 runs in the eight T20Is the venue has hosted this year, whereas from 2015 to 2020, the average first-innings score was 150. The overall average score in the first innings at this ground is 152. New Zealand beat Bangladesh by a big margin while defending 128 on Sunday. Last month, Bangladesh won three games defending 122, 127, and 131 against Australia.

The overall scoreline for the Australia series was 4-1 in Bangladesh's favour and the hosts currently lead New Zealand 2-1. Together with their 2-1 win in Zimbabwe in July, Bangladesh have turned around their form in T20Is, having spent the last five years with the second worst record among the major Full Member or Associate teams. The bowling unit's accuracy and wicket-taking ability has contributed to the wins at home, but it hasn't always been one-way traffic. On Sunday, New Zealand's crushing victory was a reminder that these pitches are not favourable to any one batting side.

ESPNcricinfo has learned that the Bangladesh batters were left "confused" with the pitch on Sunday. Initially, seeing New Zealand opener Finn Allen bat, many of the home team's players felt it would be a good batting track. But the pitch unraveled quickly with all its sharp turn, uneven bounce and slowness. Bangladesh were bowled out for 76, but this muddle about the pitch has been the prevailing feeling within the Bangladesh dressing-room since the Australia series.

After winning the first game against New Zealand quite easily, Shakib Al Hasan criticised the pitches as being 'difficult'. And, the home side's team management, it is understood, have also not got the batting-friendly T20 pitches they wanted in Dhaka. Ahead of this series, head coach Russell Domingo said that they wanted pitches where teams can get "150-160," but after losing the third game, he said that they probably expected more from the pitch than they ultimately got.

"(New Zealand's 128) was probably a par score. We were hoping (the pitch) would skid on a little bit like it did the other night (on Friday). The wicket didn't get better, it probably got worse. But having been 20 from two overs, needing another 110, I am disappointed with the way the game finished," Domingo said.

In their last three T20I series, Bangladesh's collective batting average has fallen from 28.82 (vs Zimbabwe) to 15.97 (vs Australia) to currently 14.68 (vs New Zealand). They have had to heavily depend on Shakib and Mahmudullah to rescue them from poor starts and take the innings deep.

Mahmudullah has scored the only half-century in the last two series, while Shakib has tried to impose himself on the opposition's bowling attacks, with mixed results. Mushfiqur Rahim, who missed the Australia series, has looked scratchy against New Zealand in the three innings he's played so far. But while his experience offers the potential of him finding a way to score runs on these pitches, the younger and less-established batters have suffered because of these conditions.

Bangladesh have tried out three opening pairs so far in the series against Australia, Zimbabwe, and New Zealand. Among them, Mohammad Naim has batted at a strike rate of 86.22, with Liton Das or Soumya Sarkar at the other ending playing the big shots in the powerplay. If they failed, Naim tried to bat for at least ten overs. Mahedi Hasan, meanwhile, has been used as a floater, sent in to open once and at times batting at No. 3. But he, too, struggled to put together any meaningful innings. Afif Hossain and Nurul Hasan, for their part, have put together one match-winning partnership against Australia. They have generally made small contributions, and looked mostly comfortable batting ugly.

The T20Is against Zimbabwe, Australia and New Zealand are part of Bangladesh's build-up to the T20 World Cup, so these are likely to be the side's main batters for the world tournament, too. As a result, there's disappointment at every level in the BCB, as well as the Bangladesh team, with holding the T20Is on such pitches.

That said, there are mitigating factors too. The 66 matches held at this venue are the most by any ground in the world this year. Forty-nine of those matches were during the Dhaka Premier League T20s in May. The two months between that tournament and the Australia series should have been ample time for preparing the square, but it was under covers for most of the time. The monsoon season was heavier than usual this year, so even after the Australia series, three weeks in August were never going to be enough as the rain continued on most days.

After New Zealand were bowled out for 60 in the first game, BCB's cricket operations chairman Akram Khan said that rain prevented proper preparation of the pitches, and, significantly, both Australia and New Zealand requested to play only in Dhaka. This also played a role in the under-prepared surfaces.

"It wasn't bad just for New Zealand, it is the same pitch for both sides. Our players also struggled to score runs," Khan said. "We have to understand that due to the rain, it is hard to prepare the wickets. It has been mostly under covers. The wickets we get in January or February, we won't get at this time of the year.

"It is unrealistic to expect good wickets now. We obviously know that our preparation (for the T20 World Cup) would be better if we played on good wickets. The other problem is that we are only playing in Dhaka. We wanted to hold the matches in two venues but both Australia and New Zealand wanted to play in one venue. The wickets need rest."

On the bright side for Bangladesh, they are, at least winning matches in a cluster now, after going through a ten-match winless phase earlier this year. Shakib likened this winning phase to how Bangladesh prepared for the 2007 World Cup by winning a lot of matches, albeit against Zimbabwe, Kenya and Scotland, and taking that confidence to the world tournament.

Bangladesh, however, ought to be careful. Their own home-Test strategy, similarly spin-oriented, has backfired in recent times with a second-string West Indies side beating them convincingly earlier this year. Playing on such pitches ahead of a T20 World Cup, where the surfaces are going to be more batting-friendly, doesn't just diminish the batters' confidence, it could also lull their bowlers into a comfort zone. Moreover, the bowlers are also heading into the T20 World Cup without adequate match-practice of bowling on a flat pitch, which could be as damaging as any potential lack of confidence among the batters.

Mohammad Isam is ESPNcricinfo's Bangladesh correspondent. @isam84