India lifted the Asia Cup after routing defending champions Sri Lanka by 10 wickets in the final with Mohammed Siraj claiming a career-best 6-21, including four wickets in one over, at the R Premadasa Stadium on Sunday.

Electing to bat, Sri Lanka were bundled out for a paltry 50 in 15.2 overs with five batters getting ducks in their sorry-looking scorecard with Siraj the wrecker-in-chief.

Siraj's fiery display of pace bowling was best illustrated in his second over when the right-arm quick dismissed Pathum Nissanka, Sadeera Samarawickrama, Charith Asalanka and Dhananjaya de Silva.

Hardik Pandya bagged three wickets while Jasprit Bumrah claimed one as Sri Lanka registered their second lowest total in one-day internationals, lasting only 92 balls.

India needed 6.1 overs to achieve the target for a timely boost before their home World Cup beginning next month.

"It's like a dream," Siraj, who became only the fourth bowler to take four wickets in an over in ODIs, said after the Sri Lanka innings.

"I got four early wickets last time I played Sri Lanka [earlier this year] but unfortunately I could not register a five-wicket haul.

Bumrah removed Kusal Perera in the first over to trigger a collapse and the Sri Lanka batters looked helpless as Siraj breathed fire with the new ball.

Only Kusal Mendis [17] and Dushan Hemanta, who made 13 not out, managed double digits for the home side.

India skipper Rohit Sharma held himself back and sent out Ishan Kishan to open the innings with Shubman Gill, opting for a left-right opening stand.

The openers scored freely to ensure there was no drama and Kishan, who made 23 not out, scored the winning run of the summit clash, which lasted only 21.3 overs.

Gill, the tournament's leading scorer, remained unbeaten on 27.

Sri Lanka coach Chris Silverwood bemoaned his team's "below-par" performance with the bat.

"The way we got dismissed is very disappointing. I think there's a lot of reflection to be done in the dressing room," he said.

"I thought Siraj was superb ... the Indian bowlers made our life difficult but, at the same time, I think we made our own life difficult as well."

India host Australia in a three-match ODI series later this month and the teams will clash again on October 8 in their World Cup opener in Chennai. (Reuters)