Najmul Hossain Shanto began his second stint as Bangladesh captain with a classy knock against Ireland in the just-concluded first Test in Sylhet, bringing up his eighth Test hundred.

Bangladesh sealed an innings-and-47-run win, with more than four sessions to spare, after wrapping up the final five Irish wickets on the fourth morning on Friday.

Shanto said he keeps captaincy out of his mind when he is at the crease. "I always say that when I'm batting, I prefer to play as a batsman. I don't think even once in my mind that I'm playing as a captain," Shanto told reporters after the match.

"I focus on how I can contribute as a batter. That's the main focus, and when I'm off the field or fielding, I try to fulfil my responsibilities as captain."

He had gone through a difficult spell since the Sri Lanka Test series, when he stepped down as skipper. Shanto acknowledged it was a challenging period, but he used the time to refocus and work on his batting.

"The first few days were tough, to be very honest. But yes, after that, I became quite relaxed and enjoyed the whole time. I gave time to myself, as well as to my family, and worked on how I could further improve my cricket, skill-wise and mentally. But I think that time passed very well for me."

Shanto scored two centuries in Sri Lanka earlier this year, but against Ireland in Sylhet he looked more like his earlier self -- playing straight, staying in the 'V', and putting away anything in his hitting arc.

"There is no such difference," he said. "I think if I talk about this innings, I was able to utilise all the bad balls I got. That was a positive aspect, and the focus is always on that because, at the international level, the number of bad balls is very low. So, utilising those bad balls as well as possible is important. I feel good about being able to do that," he added.

Asked whether he had made any specific adjustments against spin, Shanto played it down.

"I didn't play many sweeps in this innings. I think I played one sweep and some paddle sweeps. Nothing like that; I tried to play on the merit of the ball," he reiterated.