Pakistan recovered from Thilan Thushara's twin strikes to reach 103 for two at lunch on the opening day of the third and final test on Monday.
Opener Khurram Manzoor was 42 not out with the experienced Mohammad Yousuf on 36 after Sri Lanka skipper Kumar Sangakkara won the toss and asked Pakistan to bat first.
Yousuf and Manzoor have added 67 runs for the unbroken third wicket to rescue the innings from 36 for two.
Sri Lanka, already 2-0 up in the series, had Pakistan in early trouble when left-arm paceman Thushara removed opener Fawad Alam (16) and skipper Younus Khan (2) as the ball swung and seamed in overcast conditions in the morning.
Thushara bowled an incisive seven-over spell after being brought on as first change before striking in the 12th over.
Alam, who scored a magnificent hundred on debut in the second test, was caught behind before Khan chopped a wide delivery onto the stumps.
Sri Lanka included left-arm paceman Chaminda Vaas for his farewell test match, replacing spinner Ajantha Mendis in the only change from the second test which the hosts won by seven wickets.
Pakistan replaced seamer Abdur Rauf with leg spinner Danish Kaneria.