England 194 for 3 (Roy 65, Root 61) beat Pakistan 260 for 6 (Azhar 82, Sarfraz 55) by 44 runs (DLS method)
Sorecard and ball-by-ball details

This was another sign of the reversal of England's fortunes in the Test and one-day formats. Where they had been stretched by Pakistan during a closely contested 2-2 Test series draw, they rebounded with elastic potential during the first ODI to be well ahead of the Duckworth-Lewis-Stern requirement when rain returned in the evening to curtail a processional run chase.

Half-centuries for Jason Roy and Joe Root ensured that England would make light work of a target of 261 - revised down to 252 after an initial delay and ultimately pegged at a DLS par score of 149 - and take a 1-0 lead in the series. An encouraging comeback from Mark Wood in a solid all-round bowling effort meant that Pakistan never looked like getting away, with Azhar Ali's return to form the one bright spot for the tourists.

Roy required the attention of England's physio, having suffered a dizzy spell after running two in the fourth over, and was badly missed by the wicketkeeper, Sarfraz Ahmed, on 24 but shrugged off such inconveniences to cruise along at more than a run a ball. His fifty came off 43 deliveries and it was something of a surprise when he miscued a wild slog at Mohammad Nawaz, which was well-taken by Babar Azam running along the boundary rope at long-off. His 65 off 56 was the first time since his maiden ODI century last year that he had not converted a fifty to three figures.

Pakistan needed wickets to compensate for their lack of runs but, on a typically true Ageas Bowl surface, Root calmly ushered England past the 150 mark - only to then be caught short by a misjudged call for a single by his captain, Eoin Morgan. Neither Morgan nor Ben Stokes, making his England comeback after a calf tear, looked in the best of nick (only Stokes, with two T20 innings for Durham, had batted previously this month) but they cobbled together enough loose change to keep England well ahead as showers swept in at the end of a muggy day on the south coast.

Azhar's highest ODI score since making a century against Zimbabwe in Lahore last May and some effective scampering from Sarfraz had provided a platform for Pakistan but the late charge towards 300 never really materialised. From 199 for 4 after 40 overs, they could only manage to add a further 61 runs, giving them the lowest first-innings total in an ODI at the ground (from a full 50 overs) since England made 256 for 6 against Pakistan in 2010. Pakistan failed to clear the ropes at all and only four boundaries were scored in the final ten; only four runs came from the last over.

Roy then cracked three fours from four balls in the third over of the chase as England's one-day buccaneers signalled that a requirement of little more than five an over was unlikely to daunt them. Alex Hales fell early, once more punished like a miscreant schoolboy for playing in the corridor, but England were 66 for 1 after the opening Powerplay and, as Roy swept the first and only six of the match over the head of the man stationed at deep square leg to bring up a fifty stand with Root off 42 balls, the direction of travel was clear.

Pakistan had won the right to make first use of an oatmeal-coloured surface, with Azhar patiently compiling 82, his first ODI half-century in 13 innings, and although he could not push on to three figures, he glued the innings together for long enough to give his side a chance. That they could not fully cash in was as much down to some excellent death bowling as a failure of Pakistan's lower-order hitters.

Azhar put on half-century stands with Babar Azam and Sarfraz, following a cagey opening in which Wood's pace caught the eye, but after the 43rd over was interrupted by a 20-minute rain delay Pakistan lost their way. Sarfraz and Shoaib Malik perished in identical fashion, chipping wastefully to mid-off, and Chris Woakes was particularly impressive as the southpaw allrounders Nawaz and Imad Wasim struggled to raise the tempo.

Wood, making his first international appearance since England's tour of the UAE last year, was consistently above 90mph in his opening spell - his ankle no longer impeding his ability to throw his body through the crease - and he claimed the first wicket of the day, Sharjeel Khan getting a thin top edge on a pull, confirmed by the Snickometer after a review, after biffing a few early boundaries.

Pakistan finished the initial Powerplay on 45 for 1, though Azhar was a touch fortunate to still be at the crease after twice being dropped on 9. The first, off the bowling of Woakes, was a straightforward chance to Hales in the gully - though he gestured that he hadn't picked the ball out of the crowd - and then in the following over, Plunkett's first, Jos Buttler could not hold on to a leg-side nick diving one-handed to his left.

England snuffled out a bonus wicket through Root's part-time offspin, as Mohammad Hafeez did little to suggest the change to a white ball would improve his form by top-edging a casual-looking sweep straight to deep backward square leg, but Azhar and Azam found their range with a 61-run stand in 70 balls to take Pakistan into three figures.

The nimble-footed Azam scored two-thirds of those runs and was looking increasingly fluent but, a ball after carting a dragged-down Adil Rashid delivery just short of the rope at wide long-on, he received a poor decision from umpire Simon Fry. Defending with bat close to his front pad, replays revealed a clear inside edge but, with Sharjeel having wasted Pakistan's one review, Azam had to make his way off lbw to Rashid for 40.

The default setting for Pakistan's limited-overs captain seems to be "under pressure" but Azhar had accepted the situation with a laugh and a shrug on the eve of the match. Without a series win since beating Zimbabwe 2-1 in October, Azhar had also not passed fifty in over a year, so the sight of Pakistan's leader raising his bat in the 29th over was heartening for a healthy contingent of flag-waving supporters at the Ageas Bowl - even if it took 84 balls to get there.

Azhar attempted to forge on after reaching his half-century, bludgeoning five more boundaries over the course of the next six overs to take his stand with Sarfraz to 65, but he was then undone by a some extra bounce for Rashid, a top edge looping to Moeen Ali running across from short third man. Barely had the pressure released before it was mounting once again.

Alan Gardner is an assistant editor at ESPNcricinfo. @alanroderick