Pakistan won the preceding three-Test series 1-0, but their captain Misbah-ul Haq feared a strong comeback from the Sri Lankans, who are number two in the world to their opponent's sixth in ICC (International Cricket Council) rankings.
Sri Lanka also finished runners-up to India in this year's World Cup, where Pakistan were the losing semi-finalists.
Pakistan beat Sri Lanka in the group stages of the 2011 World Cup and that's why Misbah feels both teams will start on an even keel.
"Sri Lanka are a very good one-day side, so we know we face good competition but we are focused and I believe it's a 50-50 game because if they reached the final of the World Cup, we were semi-finalists," said Misbah.
The 37-year-old Misbah was appointed captain for all three formats of the game in June this year after Shahid Afridi retired in protest over being sacked as one-day captain.
Afridi, who with 21 dismissals was the joint-leading wicket taker in the World Cup with India's Zaheer Khan, returns to the squad after reversing his retirement decision earlier this month.
Misbah hoped Afridi's return will boost Pakistan.
"Afridi is a very good allrounder and whenever he plays he is a threat for the opponents," said Misbah of Afridi who holds the record of the fastest one-day hundred, made off 37 balls against Sri Lanka in 1997.
But the 31-year allrounder will be under pressure to perform in both batting and bowling after a poor one-day series against the West Indies in May, following which he fell out with then coach Waqar Younis.
Sri Lanka will also be boosted by the return of their sling-action paceman Lasith Malinga who earlier this year retired from Test cricket, but still poses big threats in limited over matches with his lethal yorkers.
"Lasith gives us good bowling support at the top and that is why we have a decent one-day team and had a good one-day series against Australia at home two months ago," said Sri Lankan captain Tillakaratne Dilshan.
But Dilshan has no series wins as captain, both in Tests and one-day, since taking over from Kumar Sangakkara in May this year.
The 35-year-old opener still believes his team carry some positives from the Test series.
"We can carry the positives from the Tests, our bowling is really experienced with Lasith and Dilhara (Fernando), both have played well and our batting is strong, so we have a good chance," said Dilshan.
The remaining matches will be played in Dubai (November 14 and 18), Sharjah (November 20) and Abu Dhabi (November 23). The sides will also play a Twenty20 in Abu Dhabi on November 25.
