Pakistan rose to the top of the one-day international rankings with a 59-run win against Afghanistan in the third and final match in Colombo on Saturday, claiming a 3-0 series whitewash.
Pakistan were helped to 268-8 in 50 overs by a solid 79-ball 67 from Mohammad Rizwan and an 86-ball innings of 60 from skipper Babar Azam.
They then dismissed their opponents for 209 in 48.4 overs with number nine Mujeeb Ur Rahman top-scoring for Afghanistan with a 37-ball 64 for his maiden half century.
Rahman smashed five sixes and as many boundaries, racing to a new Afghan record for the fastest ODI fifty off just 26 balls before he stepped on to his stump and was out hit wicket off Shaheen Shah Afridi.
Rashid Khan was the previous record holder for Afghanistan with a 27-ball fifty against Ireland in Abu Dhabi last year.
Rahman and Shahidullah Kamal (37 off 65 balls) shared a valiant stand of 57 for the eighth wicket to give some respectability to the total after their team were reeling at 97-7.
Rahman also added 45 for the ninth wicket with Fareed Ahmad Malik who scored 17.
Pakistan won the first match by 142 runs and by one wicket in the second -- both games played in Hambantota.
Pakistan had been at number two in the International Cricket Council ODI rankings before the series but the 3-0 triumph lifted them above Australia.
Pakistan were briefly number one earlier this year.
Pakistan medium pacer Faheem Ashraf removed Rahmanullah Gurbaz, who made a century in the last game, for five and Ibrahim Zadran for an 11-ball duck to finish with 2-43.
Pakistan rested frontline bowlers Haris Rauf and Naseem Shah in four changes but they were still good enough with the ball as spinners Shadab Khan (3-42) and Mohammad Nawaz (2-45) shared five wickets.
"Yes, we are number one," said Azam, who is also the number one batsman in the ODI rankings.
"All credit to boys. We have worked hard for the last of couple of months and it has taken us to this point, so I am really happy."
Afghanistan skipper Hashmatullah Shahidi admitted his team was not up to the mark.
"We didn't apply ourselves," said Shahidi. "We are disappointed with the performance but there is a lot of learning."
It was Rizwan and Azam who anchored Pakistan's innings after they won the toss and batted.
Rizwan hit six boundaries and a six while Azam knocked four boundaries and a six to help Pakistan to a fighting total.
The Rizwan-Azam pair added 110 runs for the third wicket to steady the innings after pacer Gulbadin Naib removed openers Fakhar Zaman (27) and Imam-ul-Haq (13).
Pakistan stuttered in the middle overs with four wickets lost for the addition of just 27 runs, including Azam's wicket who scored his 28th half century.
Saud Shakeel was run out for nine and Shadab for just three as Pakistan were struggling at 189-6.
Agha Salman (38 not out) and Nawaz (30) added 61 for the seventh wicket as Pakistan added 80 in the last ten overs.
Salman hit four boundaries and a six in his 31-ball quickfire knock.
Naib was the pick of Afghanistan bowlers with 2-36.
The two teams will now feature in the six-nation Asia Cup starting in Multan from August 30.