Sri Lanka 165 for 5 (Gunathilaka 57, Avishka 33, Rajapaksa 32, Hasnain 3-37) beat Pakistan 101 (Udana 3-11, Pradeep 3-21, Hasaranga 2-20) by 64 runs
Sri Lanka rode to 165 for 5 on Danushka Gunathilaka's rapid fifty, before the bowlers shut Pakistan down in unexpectedly ruthless fashion, taking three early wickets before wiping out the remainder of the batting order through the middle overs.
Against the No. 1-ranked T20 side in the world, Sri Lanka's 64-run victory was a substantial upset. The attack did not have the skill or leadership of Lasith Malinga, and yet produced a supreme team performance, Nuwan Pradeep and Isuru Udana taking three wickets apiece, Wanindu Hasaranga claiming two, and Kasun Rajitha one. Even Lakshan Sandakan, who went wicketless, played an important role in Sri Lanka's defence, conceding just 24 from his four overs.
Pakistan's only major joy was fast bowler Mohammad Hasnain's hat-trick, completed across two overs. He got Bhanuka Rajapaksa lbw at the end of the 16th over, before getting Dasun Shanaka and Shehan Jayasuriya to hole out at the start of the 18th. Hasnain is the ninth bowler to take a hat-trick in T20Is, and at 19, is the youngest to do it.
Beyond a 46-run fourth-wicket partnership between Sarfaraz Ahmed and Iftikhar Ahmed, which ended in an awful run-out, Pakistan's innings struggled for substance. No batsman crossed 25, the first three wickets fell for 22 runs, and the last seven for 33. They were all out in the 18th over - Udana the second Sri Lanka bowler to take two wickets in two balls, after Pradeep had done it earlier in the innings.
Gunathilaka played such a sublime lone hand through the early overs that when he was eventually out for 57 off 38 balls in the tenth, his opening partner Avishka Fernando had made no more than 16. His knock contained eight fours and a six over midwicket, three of those fours coming off a single Shadab Khan over, Gunathilaka biffing him through the legside, with the sweep, then the pull, then the sweep again.
Two overs earlier, he had slammed Hasnain for two offside fours as well. It was in the Powerplay that Gunathilaka wreaked the most damage, hitting 43 off 26, while the team total had sped to 64 for no loss. Avishka had struck the first four of the innings, through point, but contented himself with turning the strike over as his partner hit a high gear.
Gunathilaka reached his fifty with his only six, off Shadab, but was eventually dismissed by the same bowler, lbw to a hard-spun legbreak. Avishka never managed to raise his strike rate, getting out for 33 off 34 balls, but the momentum that had been injected to the innings was taken forward by Rajapaksa, playing his first international. He hit two sixes and two fours in his 32 off 22 balls, before captain Shanaka produced an important cameo, launching Faheem Ashraf for two legside sixes on his way to 17 off 10.
The finish could have been stronger, from the likes of big-hitting allrounders Hasaranga and Udana, but with Mohammad Amir delivering an excellent final over, Sri Lanka could perhaps be satisfied with their total.
Pradeep then improved the Sri Lankan mood significantly, when he got both the prize wicket of Babar Azam as well as that of Umar Akmal in consecutive deliveries at the end of the second over. Babar had cracked him for a regal boundary through mid-on fourth ball, but Pradeep got him to nick off next ball, debutant Minod Bhanuka diving to his right to take an outstanding first-up catch. The delivery after that, to Akmal, produced as plumb an lbw as was seen through the tour - the ball hitting the batsman's back pad in front of middle stump.
Udana then had Ahmed Shehzad playing the ball on to his stumps in the fifth over, but the partnership between Sarfaraz and Iftikhar gave Pakistan just a sliver of hope, even as the required rate mounted. Iftikhar was run out when both batsmen ended up at the striker's end after a miscommunication, however, and the remaining batsmen tumbled in quick succession after that. Sarfaraz and Asif Ali were dismissed by Hasaranga, Ashraf became Pradeep's third victim of the night, and then Udana polished the innings off.
The victory was Sri Lanka's first of the tour and they lead this three-match series 1-0.
Andrew Fidel Fernando is ESPNcricinfo's Sri Lanka correspondent. @afidelf