Seamer Tinashe Panyangara took 2-15 and his new-ball partner Tendai Chatara had in-form opening batsman Mohammad Hafeez caught at second slip for 5.
Captain Misbah-ul-Haq was batting on 31 while Azhar Ali was not out on 24 at the interval.
Stand-in Zimbabwe captain Hamilton Masakadza won the toss and elected to field first after regular captain Brendan Taylor had to be with his wife, who gave birth recently.
Zimbabwe took the field only after the Zimbabwe Cricket Union agreed to clear the players' dues before the second test next week. However, middle-order batsman Sean Williams preferred to wait for his dues to be cleared and opted out of the first test.
Panyangara then had Khurram Manzoor (11) playing his first test match after three years leg before wicket and clean bowled Younis Khan (3) in successive overs to reduce Pakistan to 27-3.
Misbah and Ali resurrected the innings with an unbroken 47-run stand. Misbah looked more aggressive than his usual watchful style and struck five boundaries while Ali was circumspect by hitting two fours among 64 deliveries.