The swing Fazalhaq Farooqi got was the big problem, Shanaka said. Kusal Mendis and Charith Asalanka fell to the quick off deliveries that moved into them. The rest of the top order struggled against Naveen-ul-Haq.
"We have to ask our batters whether they were prepared," Shanaka said. "We know that Farooqi swings the ball both ways. Naveen-ul-Haq also swings it most of the time. It's not like in our conditions; these bowlers are a bit skiddier. We have to ask that question of whether we were ready for them.
"It was a really good pitch. It was the first two overs that changed the whole situation. It's been a concern over the past two years that we haven't had partnerships upfront. That's where we should be concerned."
Afghanistan raced to the small target, losing only two wickets before they completed the victory in 10.1 overs. Sri Lanka's net run-rate will be a concern going forward too, as qualifying for the next round might come down to it.
"Losing is a normal thing, but we're too good a team to lose by this kind of margin. They bowled really well with the new ball, but we have no excuses"Dasun Shanaka
"When you lose two wickets in the first over, and four inside the powerplay [in 7.2 overs], it's really hard to get back into the game," Shanaka said. "Losing is a normal thing, but we're too good a team to lose by this kind of margin. They bowled really well with the new ball, but we have no excuses. You've got to be able to bat in any conditions."
The team that beat them has the chance to take it all the way, though, Shanaka said.
Afghanistan's spin attack, led by Rashid Khan, but comprising experienced bowlers such as Mujeeb Ur Rahman, and Mohammad Nabi, has long been their strength. But with the quicks now among the wickets, and the likes of Rahmanullah Gurbaz (40* in 18 balls) and Hazratullah Zazai (37 in 28) batting well, they may be serious contenders.
"These are their home conditions, so if their batsmen come good in the tournament, they have a really good tournament, they have a very good chance to make it into the finals," Shanaka said. "There's no doubt that their bowling is world class - their spinners especially."