Dilshan (83 not out off 56 balls) steered Sri Lanka to victory in 18.5 overs after Afghanistan put up a competitive 153 for seven, courtesy a captain's knock from Asghar Stanikzai (62).
It was a morale boosting win for Lankans who suffered three consecutive losses in the Asia Cup and lost two warm-up games in the lead up to their tournament opener today.
The Afghans fought till the end but the Associate Nation's inexperience let them down. Dilshan led a successful chase and was in his elements very early into his innings, producing his signature 'Dilscoop' against Dawlat Zardan in the third over when he hit the Afghan bowler for consecutive sixes.
With Dinesh Chandimal (18 from 17 balls; 2x4, 1x6), the Sri Lankan opening duo gave them a brisk start, racing to 41 from 32 balls before before Mohammed Nabi gave the first breakthrough.
Young legspinner Rashid Khan did well in the middle but Dilshan held his nerve at the other end. Earlier, Stanikzai led from the front with a half century as Afghanistan overcame a slow start to post a challenging total.
The Lankans stifled Afghanistan top-order by reducing them to 51/4 after 11 overs before Stanikzai and Samiullah Shenwari (31 off 23) built the innings. The duo stitched 61 off 33 balls for the fifth wicket and Stanikazai got a life twice, on 34 and 44 respectively.
Stanikzai was at his explosive best towards the later stages and hit Thisara Perera's widish full length delivery over long on with one foot, reminding one of the trademark helicopter shot of Indian skipper MS Dhoni.
After Stanikzai's departure, left-hander Najibullah Zardan also had some meaty blows with a four and six against Nuwan Kulasekara in the last over. Afghanistan added 59 runs from the last five overs to set up competitive total.
The Afghans however had a terrible start with inform opener Mohammad Shahzad, who was instrumental in their qualification to the Super 10, looking out of sorts.
Shahzad had a miss-and-hit stay as Afghanistan crawled to six runs in the first two overs. Noor Ali Zardan stepped up the run rate with a 20 off 23 balls but Herath once again triggered a collapse before the Stanikzai led by example.