FORMER Somerset wicketkeeper-batsman Jos Buttler hit England's fastest one-day international hundred as the tourists piled up 355 for five against Pakistan at the Dubai International Stadium.

Buttler, who went to King's College in Taunton, scored an unbeaten 116, meaning he has now hit his country's three fastest ODI centuries. 

He smashed eight sixes and eight fours in his latest from 46 balls - the equal seventh-quickest in 50-over history.

It was especially heartening for England to see their wicketkeeper, so short of runs for much of this year, confirm his return to form in such spectacular fashion - while Jason Roy followed the example of fellow opener Alex Hales, two matches ago, by recording his first hundred at this level.

The hosts therefore had an imposing total to defend, albeit on a pitch likely to support a chase if Pakistan are in the mood.

England's openers were less than convincing early on. But the scoreboard was already telling a different tale until Hales, on 22, toe-ended an attempted pull at Mohammad Irfan to third-man, where Shoaib Malik held a running catch.

Roy had a couple of close calls.

He passed his previous career-best when he just cleared long-on off Shoaib, and then on 77 he edged a Yasir Shah leg-break but survived when the ball went through wicketkeeper Sarfraz Ahmed's fingertips and was then put down by Mohammad Rizwan at slip too.

Root was the foil who got off strike but also had the range of shot to pass his 50 in 55 balls - with a straight hit down the ground off Shoaib for his second six to add to just two fours.

It was an emotional, as well as a breakthrough, moment for Roy when he completed his century, with eight fours and that six from 113 balls.

But he got little further before skewing Yasir to long-off - and when Root was stumped, walkabout attempting a reverse-sweep to give Azhar Ali a first ODI wicket, England had two new batsmen at the crease with only a single between them.

Eoin Morgan and Buttler, promoted to number four, took 16 between them off the 40th over.

The England captain was then deceived by Azhar's googly, as his opposite number picked up a second career wicket - again stumped - and the tourists had lost three in five overs.

But Buttler and Taylor, whose unbroken century stand won the match in Sharjah three days ago, merely saw another opportunity.

Buttler produced a wonderful demonstration, full of his trademark power and ingenuity, that he is back to his best - leaving Pakistan with a huge task to avoid series defeat.