Andre Russell hit six sixes in a blistering 14-ball innings as West Indies smashed their way to a seven-wicket victory over Sri Lanka and seal the two-match Twenty20 series on Friday.

West Indies' bowlers limited Sri Lanka to 155 for six and then Brandon King struck 43 off 21 balls and Russell made 40 off just 14 balls as West Indies raced to 158 for three in 17 overs. 

The tourists also easily won the first game by 25 runs this week.

Though West Indies are reigning World T20 champions it was their first series win in the format in more than a year.

"We are peaking at the right time, but we still have some areas to work on," said Russell whose appearances have been limited by a series of injuries in recent months.

The 31-year-old frequently rubbed his shoulder during his smash-and-grab innings in which he hit one ball out of the Pallekele ground. 

No batsman has hit six sixes in so few balls in a T20 international.

Young opener King also sparkled with the bat, making 43 off 21 balls, including eight boundaries.

"The young man is finding his feet in international cricket. Russell finished it off and the bowlers were brilliant," said West Indies captain Keiron Pollard who was elated at getting back to winning ways after suffering a whitewash in the three-match one-day series against Sri Lanka. 

Dasun Shanaka was the pick of the Sri Lankan batsmen hitting an unbeaten 31 off 24 balls. 

But captain Lasith Malinga admitted his side had managed a poor total.

With 12 games before going to the World T20 in Australia in October, Malinga said his team needed to "find consistency and confidence."