Sri Lanka needed 137 runs to win the second Test after Pakistan were bowled out for 359 in their second innings on the fifth and final day in Dubai on Sunday.
Sri Lankan paceman Suranga Lakmal ended Sarfraz Ahmed’s resistance in the fourth over of the day for 74 as Pakistan lost their last three wickets for an addition of 29 runs after resuming at 330-7.
Misbah-ul-Haq top scored for Pakistan with 97 while Suranga Lakmal picked up 4 wickets for the Lankans.
Lakmal finished with 4-78 while Nuwan Pradeep, Shaminda Eranga and Rangana Herath took two wickets apiece.
Sri Lanka have 80 overs to reach their target and take a 1-0 lead in the three-match series after the first Test ended in a draw in Abu Dhabi last week.
The third and final Test starts in Sharjah on Thursday.
Pakistan resumed on 330 for seven, enjoying a lead of 107 runs, in their second innings on the final day of the second Test at Dubai International Stadium.
Play began half an hour early amid overcast conditions and the floodlights on at the ring of fire.
