Bangladesh captain Mashrafe Mortaza said that the side's improved performance since the 2015 World Cup should not be forgotten even as they find themselves scrambling to avoid an embarrassing series loss to Afghanistan ahead of the third ODI in Mirpur on Saturday.

"We definitely have the confidence and belief to win the series," Mashrafe said. "I don't think that one defeat will end all the work that we have done and all our achievements so far. We were all obviously disappointed but that doesn't mean that we have forgotten all the good work that we have done. It was a bad day. If we think about that when we get on the field it will be difficult for us, so we are trying to get on the field with a free mentality."

He said that Afghanistan would deserve the ODI series win if they go on to beat Bangladesh in the third game, and added that they never took their opponents lightly at any point.

"[If they win the series] I will feel that they are deserving winners. In the past, we won many matches and people called them upsets, but we didn't accept them as upsets. It is not right. They should definitely get the credit.

"We never took them as an easy opponent, which was clear after the first game. In the second match our batting collapsed. At one point we recovered, but still we kept losing wickets. We couldn't play our best game."

Bangladesh's batsmen have been guilty of throwing their wickets away after spending some time in the middle. While they reached 265 in the first game, Tamim Iqbal and Mahmudullah got out at the wrong time and Shakib Al Hasan was unable to press on from his 48. In the second game, it was their entire top five - Tamim, Soumya Sarkar, Mahmudullah, Mushfiqur Rahim and Shakib - who failed to convert starts to big scores.

Perhaps treating a bowling attack from a lower-ranked team with disregard was a contributing factor, especially given how Tamim and Soumya got out in the second ODI. Mashrafe said that his batsmen could learn from the way someone like Kumar Sangakkara played Bangladesh in the past, and apply those lessons when facing Afghanistan.

Sangakkara is the highest run-getter against Bangladesh in Tests and ODIs, including a triple-hundred and two double-hundreds in Tests and another nine 100-plus scores across both formats.

"We have all discussed this in the dressing room. If someone can score a 150, then it becomes a big deal for his career. Kumar Sangakkara has scored so many 150s and 200s against us. I am sure that our batsmen aren't taking them lightly. Maybe there was a bit of a break in concentration.

"We are all mature individuals. If you see the top five batsmen in our line-up, at least one of them scored big in each game in the last 18 months. But when they don't, we will always get a low score."

Mohammad Isam is ESPNcricinfo's Bangladesh correspondent. @isam84