Sri Lanka spinner Maheesh Theekshana ruled out of Asia Cup final against India

Bowler picked up hamstring injury during victory over Pakistan and misses Sunday's game in Colombo

Sri Lanka's Maheesh Theekshana will miss the Asia Cup final due to a hamstring injury. AFP

Sri Lanka have suffered an injury blow ahead of the Asia Cup final against India on Sunday with spinner Maheesh Theekshana ruled out due to injury.

Theekshana, 23, strained his right hamstring while sliding near the boundary in Sri Lanka's victory over Pakistan and needed treatment from the physio.

He bowled three more overs before being helped off the field during his team's thrilling two-wicket win on Thursday.

Sahan Arachchige has been called up as his replacement for the final in Colombo, where Sri Lanka will aim to retain their title.

Theekshana will “definitely be ready” for next month's 50-over World Cup in India, which starts on October 5, according to Professor Arjuna de Silva, chairman of Sri Lanka Cricket's medical committee.

“The MRI scan is showing a tear – not a big tear,” he said. “Clinically, Theekshana is OK. He's moving around and not feeling too much pain.

“If we didn't have a World Cup coming up, we would have somehow tried to get him ready for tomorrow's match. But we don't want to take that risk.”

Sunday's final sees Rohit Sharma's India face underdogs Sri Lanka with both teams gearing up for next month's World Cup.

The cricketing giants have 13 Asian titles between them and Sri Lanka have a history of sneaking into the tournament's final – to the consternation of fans keen for any showdown between arch-rivals India and Pakistan.

Bangladesh ended India's unbeaten run in the 50-over tournament after edging them out by six runs in Friday's last Super Four match.

Shubman Gill hit 121 but his knock went in vain after India faltered in their chase of 266 in Colombo.

“I don't think it has broken our momentum,” Gill told reporters after the narrow defeat.

“We have played good cricket. Sometimes it happens on these wickets. I was set and should have finished off the game.”

Gill said clinching India's eighth Asia Cup title would give them “confidence” ahead of the World Cup taking place back home.

India began with a washed-out match in Pallekele against Pakistan, whose fast bowlers rattled their top order and bowled them out for 266 in the only innings possible due to rain.

Big guns Virat Kohli and returning batsman KL Rahul hit back with centuries in their next outing against Babar Azam's team to rack up 356-2 and crush Pakistan by 228 runs.

India then prevented a gutsy Sri Lankan chase to book their place in the final, but Gill said their opponents were still a threat.

“We will have to pull up our socks and be at our 100 per cent to beat them,” he said.

Sri Lanka, who won the previous edition of the Asia Cup played in the T20 format, came in as underdogs and snuck into the Super Fours with a dramatic win over Afghanistan.

They soon got into their groove on home soil and, despite going down to India, edged out Pakistan in a knockout match for their 11th Asia Cup final.

“We came without our key players, but still we managed to make the finals,” captain Dasun Shanaka said.

Injuries sidelined Dushmantha Chameera and Wanindu Hasaranga, but others stood up at crucial junctures.

Kusal Mendis and Charith Asalanka both hit match-winning knocks to take the team over the line in a rain-shortened match and push a much-favoured Pakistan out of the tournament.

Up-and-coming fast bowler Matheesha Pathirana and left-arm spinner Dunith Wellalage have impressed and lead the tournament's bowling chart with 11 and 10 wickets respectively.

Wellalage rattled India's batting with five wickets including the prized scalps of Kohli and Rohit in their Super Four match.

Twice before in the Asia Cup Sri Lanka have lost to India in the Super Four stage only to beat them in the finals, in 2004 and 2008.