The Pakistan board removed Arthur and his support staff, following the side's fifth-place finish at the ICC World Cup 2019 in England and Wales.
Pakistan went on to rope in Misbah-ul-Haq as the head coach.
Under Misbah, Pakistan won the ODIs against Sri Lanka.
However, they lost the T20Is.
Key information about Arthur, Flower and Saker
Arthur will be Sri Lanka's 11th coach in the last eight years. Flower was associated as the head coach of Bangladesh Premier League side Rangpur Rangers. Meanwhile, Saker, who has been involved with the likes of England and Australia, was bowling coach of USA.
A look at Arthur's tenure with Pakistan
Arthur took over the mantle in mid-2016.
Under his tenure, Pakistan won the ICC Champions Trophy in 2017.
The team also grabbed the number one spot in the ICC's T20 Rankings.
Pakistan's performance in Test cricket dipped drastically and in ODIs too they kept struggling.
This meant that he had to go and the 2019 World Cup was a final nail in the coffin.