Sri Lankan captain Upul Tharanga won the toss and sent Pakistan in to bat in the first day-night international in Dubai on Friday.
The green shirts were upset 2-0 in the preceding Test series but they are now hoping to change their fortunes and carry the limited over form which helped them win the eight-nation Champions Trophy held in England in June this year.
Sri Lanka, who won the preceding two-match Test series 2-0, had spearhead Nuwan Perera ruled out from the one-day series with a hamstring injury and inducted Lahiru Gamage.
The remaining matches will be held in Abu Dhabi (October, 16 and 18) and in Sharjah (October, 20 and 23).
Three Twenty20 internationals will follow the ODIs, the last in Lahore on October 29.
Teams:
Pakistan: Sarfraz Ahmed (capt), Ahmed Shehzad, Fakhar Zaman, Mohammad Hafeez, Babar Azam, Shoaib Malik, Imad Wasim, Shahdab Khan, Hasan Ali, Rumman Raees, Junaid Khan
Sri Lanka: Upul Tharanga (capt), Dinesh Chandimal, Niroshan Dickwella, Lahiru Thirimanne, Kusal Mendis, Milinda Siriwardana, Thisara Perera, Lahiru Gamage, Suranga Lakmal, Akila Dananjaya, Jeffrey Vandersay
Umpires:
Sundaram Ravi (India) and Ahsan Raza (Pakistan) Tv umpire: Richard Kettleborough (England) ICC match referee: Andy Pycroft (Zimbabwey)