Arsenal beat Chelsea in a penalty shoot-out in front of a bumper Dublin crowd
Alex Iwobi converted the winning spot-kick as Arsenal beat Chelsea 6-5 on penalties in a thrilling International Champions Cup clash in Dublin.
Second-half substitute Iwobi held his nerve to clinch victory for the Gunners at the Aviva Stadium after goalkeeper Petr Cech had saved from Chelsea's Ruben Loftus-Cheek.
Another Arsenal substitute, Alexandre Lacazette, had fired a deserved last-gasp equaliser for Unai Emery's side after Antonio Rudiger's early header had given Chelsea a half-time lead.
Both sides converted all five of their penalties in the shootout before England midfielder Loftus-Cheek was thwarted.
But the Gunners' win could yet be bittersweet as Emery is waiting to learn the full extent of the calf injury which forced Aaron Ramsey to be withdrawn from the starting line-up just before kick-off.
Chelsea were good value for their half-time lead but were left to rue a string of missed first-half chances after a dazzling display from teenager Callum Hudson-Odoi.
But Arsenal came into the game after the break and after a plethora of second-half substitutions they finished well on top.
Cesc Fabregas' shot, after a fine run from Hudson-Odoi, was turned behind by Cech and from the resulting corner the unmarked Rudiger rose highest to power home a header.
Hudson-Odoi was causing Arsenal plenty of problems and eight minutes later Hector Bellerin brought him down in the box following another eye-catching run by the youngster.
Alvaro Morata stepped up to take the penalty, but Cech guessed correctly and produced a comfortable save down to his right.
Bellerin was left chasing Hudson-Odoi's shadow again shortly afterwards as the 17-year-old set up Morata twice in the space of six minutes, but the Spaniard failed to convert both chances.
Arsenal spurned a golden chance to equalise when Pierre-Emerick Aubameyang somehow let Henrik Mkhitaryan's cross escape him at the far post.
Morata then completely missed another Hudson-Odoi cross and at the other end, as the game flowed, Chelsea goalkeeper Willy Caballero thwarted Sead Kolasinac.
At the end of the first period Hudson-Odoi showed his electric pace again, racing on to Fabregas's ball over the top only to be denied by the onrushing Cech.
Chelsea boss Maurizio Sarri replaced Fabregas with Danny Drinkwater and sent on Andreas Christensen for David Luiz during the interval.
Chelsea went close to a second goal when Rudiger headed Pedro's cross off target when he should have done better.
Sarri made further changes in the 63rd minute when Davide Zappacosta, Emerson, Victor Moses and Tammy Abraham replaced the Spanish quartet of Cesar Azpilicueta, Marcos Alonso, Pedro and Morata.
Emery sent on Iwobi for Smith-Rowe and soon after Ainsley Maitland-Niles, Reiss Nelson and Lacazette replaced Kolasinac, Mkhitaryan and Aubameyang.
The changes affected Chelsea's rhythm and Lacazette pulled a shot wide after he had nutmegged his way clear on goal as Arsenal continued to press.
But the Frenchman popped up at the far post to turn home Nelson's cross from the right with the last kick of the game.