Mohammad Hafeez was unbeaten on 36 at the break and with him Azhar Ali, who was batting on 11.
Pakistan won the toss and elected to bat on a flat Sheikh Zayed Stadium pitch which is expected to turn in later stages.
Shehzad was shaping well during his 64-ball knock, hitting three boundaries before he missed a delivery from spinner Nathan Lyon and was trapped leg-before.
Australian captain Michael Clarke juggled his pace bowlers before bringing Lyon in the 14th over to get the needed breakthrough.
Australia, hoping to bounce back, brought in paceman Mitchell Starc and spinning all-rounder Glenn Maxwell for batsman Alex Doolan and left-arm spinner Steve O'Keefe, preferring a three-prong pace attack with one spinner in Lyon.