Pakistan blanked Sri Lanka 5-0 in the preceding one-day series and start the Twenty20 fixtures as strong favourites as the number two-ranked side, with Sri Lanka a lowly eighth.
If Pakistan sweep the T20 series they will come within a point of first-place New Zealand and could go top if India beat the Black Caps in a three-match series next month.
Aside from winning nine straight ODIs since lifting the Champions Trophy in June, Pakistan have also won nine of their last 11 Twenty20 internationals -- all since Sarfraz Ahmed took over as captain.
That contest will see the return of Sri Lanka to Pakistan, eight years after their team bus was ambushed by gunmen on the way to the ground in Lahore on March 3, 2009.
More From This Section
The attacks, which killed eight people and left seven Sri Lankan players and a staff member injured, resulted in the suspension of all international cricket in Pakistan, forcing them to play home matches in the United Arab Emirates.
That forced Sri Lankan selectors to hand all-rounder Thisara Perera, part of the World XI, the captaincy and choose a new-look side.
But Ahmed said his team will not underestimate Sri Lanka.
"It's satisfying to win the ODIs and we will target that same winning momentum but definitely we will not take Sri Lanka lightly," said Ahmed.
Pakistan's pace bowling will be further boosted by the return of Mohammad Amir who missed the ODIs with a shin injury.
Fill-in Sri Lanka skipper Perera hopes his team will put up a good fight.
"I am really happy to be leading the team," said Perera. "It's a dream come true for me and I hope this team can do something special in this series."
Squads:
Pakistan: Sarfraz Ahmed (capt), Fakhar Zaman, Ahmed Shehzad, Babar Azam, Shoaib Malik, Mohammad Hafeez, Imad Wasim, Shadab Khan, Mohammad Nawaz, Faheem Ashraf, Hasan Ali, Aamer Yamin, Mohammad Amir, Usman Shinwari, Umar Amin.