Sri Lanka declared their second innings on 181 for six wickets to set Pakistan a target of 255 runs for victory on the rain-hit fifth day of the third and final test in Sharjah on Monday.
Resuming on 164 for five, Sri Lanka, who need a win to draw the series, batted 4.2 overs to extend their lead before declaring.
Opener Tharanga Paranavitana (76) and Rangana Herath (one) were at the crease after rain wiped off the entire session before lunch on Monday.
Kosala Kulasekara (7) played Saeed Ajmal on to his stumps to gift the off-spinner his third wicket of the innings shortly before the declaration was made.
Pakistan, who won the second match of the series by nine wickets, are playing "home" tests in the Gulf region due to security concerns in their own country.
(Writing by Sudipto Ganguly in Mumbai)