Eoin Morgan and Ravi Bopara were the stars of the show in Dublin as England recovered from a dreadful start to defeat Ireland by six wickets.
Ireland had posted a competitive score of 267-7 thanks to a brilliant 112 from captain William Porterfield before Tim Murtagh and David Johnston combined to leave England struggling at 48-4.
This brought Morgan and Bopara to the crease, with the two both hitting unbeaten centuries and recording a world record record fifth wicket partnership in one day internationals of 226 from just 169 balls to see England home with some seven overs to spare.
Victory was brought up in some style as England hit 22 from the final over, with Bopara reaching his century from just 74 balls, before captain Morgan hit another monster six to claim a memorable victory.
"I was more nervous in the changing room than I was out in the middle," said captain Morgan. "The wicket was quite challenging, a lot of what we have there we're not used to as a side and we had a challenge with the ball and the bat. Time in the middle as a batsman is crucial, especially with a big series coming up and I felt good. Incredible support from the crowd today, it's great to get nine to ten thousand in.
"Boyd Rankin played really well, he's used to conditions here but he had to go full of a length here which is not easy for a man of his height. It was tricky batting to start with when the seam on the ball was still hard, there were potentially a few nerves there with a few guys coming in."
England started the day by handing one-day international debuts to three new faces in Michael Carberry, Gary Ballance and former Ireland fast bowler Boyd Rankin.
The 29 year old would prove to be the pick of the England bowlers as he picked up the scalps of Porterfield, Paul Stirling, Ed Joyce and John Mooney.
Ireland would lose wickets at regular intervals but Porterfield's brilliant century and runs down the order from Mooney, Kevin O'Brien and Max Sorenson meant they would post what many believed would be a competitive total.
England would have felt as though it was a poor performance in the field with Carberry dropping two catches, while Steve Finn and Ben Stokes both finished their ten over spells without a wicket.
However, there was another impressive display from spinner James Tredwell who picked up the important wickets of Niall O'Brien for 26 and Gary Wilson for just two.
After a sloppy display in the field England would have wanted to make a positive start with the bat but Carberry fell for just ten, before Luke Wright was picked up by Murtagh having scored five runs from 20 deliveries.
The Middlesex seamer would then pick up the wicket of debutant Ballance for a duck before clean bowling James Taylor for 25.
Morgan, who was playing on his former home ground, would then produce a scintillating innings of 124 that included eight fours and four sixes.
He was well supported by Bopara who accelerated throughout the innings to eventually finish unbeaten on 101 from just 75 balls, as he blasted 10 fours and five sixes.
Ireland supporters may well have mixed feelings about the result as it was two Irishmen who did the damage for England as Morgan top scored, while Rankin was the pick of the away side's bowling attack.