Dhananjaya de Silva hit an unbeaten 66 as Sri Lanka kept their slim Twenty20 World Cup hopes alive with a six-wicket win over Afghanistan at the Gabba in Brisbane on Tuesday.

The Asia Cup champions bagged four points in Group 1 and can still make the semi-finals, but they need other results to go their way.

The loss means Afghanistan are eliminated as they cannot make the semi-finals with one group match against Australia remaining after having two washouts and an opening defeat to England.

Afghanistan won the toss and chose to bat but Sri Lanka restricted them to 144-8, thanks to a fine spell from leg-spinner and player of the match Wanindu Hasaranga.

The Sri Lankan run chase got off to a poor start when Mujeeb Ur Rahman spun one back to bowl Pathum Nissanka for 10.

Kusal Mendis and de Silva recovered and took the score to 46 before Afghanistan trump card, leg-spinner Rashid Khan, drew a top edge from Mendis, giving keeper Rahmanullah Gurbaz a simple catch.

Khan took the next wicket when Charith Asalanka was caught by Azmat Omarzai on the boundary for 19 but by then Sri Lanka had reached 100 and had taken control of the run chase.

De Silva played a perfectly measured innings, scoring his stylish 66 from 42 deliveries to guide the Sri Lankans home.

Hasaranga took 3-13 during Afghanistan's innings, not conceding a boundary in his four-over spell.

Afghanistan batted well in patches and looked on course for a big score, but every time they began to open up, Sri Lanka's bowlers were able to take key wicket to keep them in check.

Despite six of Afghanistan's batsmen getting a good start to their innings, none was able to convert to a big score with Usman Ghani's 27 being the best.

The target of 145 was at least 20 runs short of a competitive total and Sri Lanka cruised home with nine balls to spare when De Silva hit the winning four to take them to 148-4.