Paceman Deepak Chahar claimed the best-ever Twenty20 international bowling figures of six for seven as India clinched a 2-1 series triumph over Bangladesh with a 30-run win on Sunday.

Chahar, a medium-pace bowler, finished the match with a hat-trick to bowl out Bangladesh for 144 in 19.2 overs while chasing 175 for victory in Nagpur.

Chahar became the first Indian bowler to get a T20 hat-trick as he went past Sri Lanka's Ajantha Mendis, who had figures of 6-8 against Zimbabwe in 2012.

Left-handed opener Mohammad Naim made 81 and put on 98 runs for the third wicket with Mohammad Mithun, who made 27, but the rest of the batting faltered in the chase.

Chahar, who wiped out the tail with a wicket with the last ball of his third over and two at the start of his fourth, was ably supported by fellow paceman Shivam Dube who claimed three wickets.

It was a special effort by the Indian bowlers who found it difficult to grip the ball due to late-evening dew.

"It were the bowlers who won us the game. I know how tough it was in the middle considering the dew factor," stand-in-skipper Rohit Sharma said after the win.

"But this must be one of the best comebacks in this format for India. It was easy for them at one stage, with 70 needed in eight overs. But the boys showed characters, took up the responsibility."

The Iyer-Rahul stand

Chahar, who took two early wickets from successive balls as Bangladesh slipped to 12 for two, broke the threatening third-wicket stand after sending back Mithun.

Dube struck with the first ball of the very next over as Mushfiqur Rahim played on for a golden duck to give the medium-pace bowler his maiden T20 scalp.

Dube then got Naim's prized scalp with a perfect yorker that rattled the stumps of the left-hander and was on a hat-trick after getting new batsman Afif Hossain caught and bowled.

Earlier, Indian batsmen KL Rahul, who made 52, and Shreyas Iyer, who scored 62, helped the hosts reach 174 for five after being put in to bat first.

Iyer and Rahul put on a crucial 59-run stand for the third wicket to give the hosts a challenging total.

Rahul raised his fifty in 33 balls as he hit seven fours before falling to paceman Al-Amin Hossain.

Iyer made the most of a reprieve on nought when dropped by Aminul Islam off Shafiul to bring up his maiden T20I fifty.

Iyer took the attack to the opposition with a flurry of sixes including three successive hits over the fence off Afif.

Sharma insisted that the team will continue to find the right balance for the T20 World Cup in Australia next year.

"Until we get close to the World Cup, we got to find the right balance. There are a few guys missing, but they'll come back. Keeping everything in mind, we have few games in mind before we get into that flight to Australia," said Sharma.

"If we keep performing like we did today, it's going to be a big headache for (regular skipper) Virat (Kohli, who was rested for the series) and the selectors."

The two teams will now play two Tests starting in Indore on November 14. Kolkata will host India's first day-night Test starting November 18.