England 216 for 6 (Bairstow 82, Billings 46*, Willey 47*, Little 3-60) beat Ireland 212 for 9 (Campher 68, Rashid 3-34) by four wickets
Sam Billings and David Willey dragged England to a second victory against Ireland in three days and a series win after a middle-order collapse left them 137 for 6 in pursuit of 213.
Curtis Campher, the South African-born allrounder, had added to his unbeaten half-century on debut with a more fluent 68 from No. 7 to lift Ireland up to a respectable total, but one that had looked some way short of par when Jonny Bairstow blitzed a 41-ball 82 to break the back of the chase.
After a three-wicket burst in six balls from Josh Little, England were staring at the prospect of only a second ODI defeat to Ireland and a first on home soil, but Billings and Willey - the stars with bat and ball respectively in the first match of the series - added 79 in 14.4 overs to calm any nerves and seal a four-wicket win.
Ireland knew they needed early wickets when defending, and Craig Young provided the goods after three balls, as Jason Roy slammed a long half-volley straight to extra cover. But it looked as though it would be a chastening evening for them when Bairstow got up and running. He effortlessly picked off anything short, full, wide or straight in blitzing England's joint-fastest ODI half-century from only 21 balls, spanking Andy McBrine over long-off for six to bring it up.
Campher struck in his first over for the second time in as many games, nipping one back through James Vince's gate to peg back his middle stump, before trapping Tom Banton for a third time in his career - once for South Africa Under-19s in 2018, two in this series. Bairstow looked utterly unfazed by what was happening at the other end, racing towards his hundred, before Little's spell changed the game on its head.
Little, a bustling left-arm seamer with broad shoulders and a skinhead, had starred on ODI debut against England last year, taking 4 for 45 to rattle England in their World Cup build-up. Things had not gone to plan in between, with one wicket for 217 in his next 28 appearances, and he was wayward in his first spell after being drafted in for the injured Barry McCarthy.
But in his second, he nicked off Bairstow with a length ball that he looked to force through the off side before spitting a volley in his direction. Then, he removed England's captain for a duck, just as he had in Malahide, digging one in short which Eoin Morgan spanked straight to (guess who?) Campher at short cover.
Three balls later it was Moeen Ali's turn to give his wicket away, top-edging a short ball towards short fine leg where Tucker ran round to take the catch. Suddenly, England needed 76 to win with only four wickets in hand. Throughout Little's spell, England's stand-in coach Paul Collingwood had been speaking to Sky from their diary room; once Moeen fell, he was running for the dressing room.
Before long, though, any nerves had been calmed. Billings was happy to play second fiddle to Willey, who pulled a towering six over long leg before whacking Campher for two boundaries to alleviate any hint of scoring pressure. They continued to rattle along to pick off the remaining runs with ease, Willey crunching Campher through square leg to seal the win with 17.3 overs to spare.
Ireland's 212 for 9 had looked short of par on a good batting wicket, primarily thanks to a middle-over squeeze from Adil Rashid and Moeen. Rashid took 3 for 34 from his 10 overs, ripping out Ireland's middle order, while Moeen bowled typically tight lines to conceded only 27 from his eight. Reece Topley bowled with good pace in his first appearance since 2016 after a string of serious injuries, taking 1 for 31 from his nine overs.
Andy Balbirnie had demanded "more application" from his batsmen at the toss, but there was little sign of that against the new ball. Gareth Delany was trapped plumb in front by a Willey nip-backer for a 12-ball duck, and with the onus on Paul Stirling to make a meaningful total, he only managed to slice the same bowler to Banton at backward point.
The low moment for Ireland came when the fielding restrictions were lifted. Balbirnie had hit two sweet boundaries, a straight drive off Willey and a sweep off Rashid, when Morgan sprung a surprise by giving Vince his first bowl in a limited-overs international.
He looked perfectly serviceable but totally unthreatening, but with Balbirnie's mind scrambled, stuck between attack and defence, he pulled out of a cut shot to a back-of-a-length ball, edging tamely through to Bairstow. Vince grinned sheepishly, almost apologetic that he had taken his first international wicket; in the absence of fans, you could just about make out a collective groan from the away dressing room.
Rashid then took control, bowling Kevin O'Brien with a googly that completely wrong-footed him. Harry Tector fell tamely, chipping half-heartedly to mid-on, while Lorcan Tucker's dismissal was no prettier, heaving a legbreak from wide outside the off stump down fine leg's throat while top-edging a sweep.
That left Campher, the shining light on debut on Thursday, with the bulk of the hard work to do from 78 for 5. He dug in for a 60-run stand with Simi Singh, dragging Ireland towards a defendable score, before putting his foot down alongside McBrine. They added 56 in 7.1 overs: McBrine nailed an upper-cut and smacked Willey straight back over his head, while Campher got innovative and proved he had power in his locker as well as poise.
He eventually fell swiping at Saqib Mahmood outside off, before Topley bowled a tight last over, ending with a sharp bouncer which McBrine edged behind to give him a first international wicket since the 2016 World T20.
The third game may be an opportunity for England to take a look at fringe players like Liam Livingstone and Liam Dawson, while both teams will know that they could do with a win with World Cup Super League points on offer.
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Matt Roller is an assistant editor at ESPNcricinfo. He tweets at @mroller98