Play was stopped after 67.2 overs due to poor light, bringing the day's proceedings to an early close.
Saud Shakeel remained unbeaten on 57 off 112 balls, hitting seven boundaries. Ghazi Ghori was batting on seven at stumps.
Pakistan's debutant Tayyab Arif impressed with a knock of 57 runs. Muhammad Taha also scored 51, while Babar Azam contributed 50.
Azaan Awais made 30 runs, while Salman Ali Agha scored 16.
Despite several promising starts, no Pakistani batter managed to convert a half-century into a bigger innings.
For Sri Lanka, Asitha Fernando claimed two wickets. Dilshan Madushanka, Milan Rathnayake and Sonal Dinusha took one wicket each.
Pakistan scored 67 runs and lost two wickets in the final session.
Earlier, Sri Lanka won the toss and elected to field. Sri Lankan captain Kusal Mendis said his team had included four fast bowlers in the playing XI.
Pakistan captain Babar Azam said his side would focus on playing to its strengths, particularly during the opening session.
Four Pakistani players made their Test debuts in the match: Tayyab Arif, Muhammad Taha, Arafat Minhas and Saqib Khan.
The other members of Pakistan's playing XI included Babar Azam, Azaan Awais, Saud Shakeel, Salman Ali Agha, Mohammad Abbas, Razaullah and Ghazi Ghori.
The second day's play is scheduled to begin at 9:30am Pakistan time on Tuesday.