Pakistan's newest skipper Sahibzada Farhan hit a swashbuckling half-century to guide Pakistan to a four-wicket win over Sri Lanka in the first T20 international in Rawalpindi on Friday.

Sahibzada Farhan smashed a half-century in the T20I series opener against Sri Lanka. (AP Photo/Anjum Naveed)

Farhan, appointed captain last month, smacked 89 off 53 balls with 10 fours and four sixes, guiding Pakistan to their target of 183 in 18.5 overs.

The win gives Pakistan a 1-0 lead in the three-match series.

Sri Lanka posted 182-8 as opener Lahiru Udara struck 91 off 55 balls after the tourists won the toss and batted.

Farhan and Fakhar Zaman got the hosts off to a rollicking start of 54-0 in five overs as Sri Lanka's attack failed to stop the flow of runs, with Zaman scoring 21 off 13.

Maaz Sadaqat kept the momentum flowing as he hit three sixes and four fours in a brisk 50, adding 92 runs with his skipper to lead Pakistan to within sight of victory.

Pakistan lost Hasaz Nawaz and Saim Ayub cheaply before Farhan was caught in the deep, but it did not derail their chase.

Earlier, Udara hit the highest T20 score by a Sri Lankan against Pakistan, improving upon Kusal Perera's 84 in Dubai in 2013.

Udara added 60 runs for the third wicket with Kamindu Mendis (23) after a poor start saw captain Kusal Mendis dismissed for one and Kamil Mishara depart for six, helping the team recover from 18-2.

Dasun Shanaka offered brief support as he and Udara added 57 for the fifth wicket, with Sri Lanka taking 66 runs off the last six overs.

Fast bowler Naseem Shah grabbed 3-36 for Pakistan, while debutant Mohammad Imran took 2-21.

The remaining two matches are on Sunday and Tuesday, both in Rawalpindi.