The Gunners managed to keep a clean sheet for most of the game and could have even scored themselves but the MSN – Messi, Neymar, Suarez – combined to deadly effect to open to scoring on 71 minutes.
Suarez and Neymar hit Arsenal on a breakneck counter-attack before the Brazilian international passed to Messi who took a cheeky touch before blasting the ball past Petr Cech.
Things got worse just minutes later. Flamini brought down Messi inside the box just 40 seconds after being brought on and the Argentinian magician did not miss from the spot.
Mesut Özil started for Arsenal but was unable to provide an assist although had his teammates not been as profligate he could easily have set up a goal or two.
Barca were without Turkish international Arda Turan due to suspension but we will be available for the return leg at the Camp Nou.
Arsenal 0-2 Barcelona
Stadium: Emirates Stadium
Arsenal confirmed starting line up: Cech, Bellerin, Mertesacker, Koscielny, Monreal, Coquelin, Ramsey, Oxlade-Chamberlain, Ozil, Alexis, Giroud
Subs: Ospina, Gibbs, Chambers, Flamini, Campbell, Walcott, Welbeck
Manager: Arsene Wenger
Barcelona confirmed starting line up: 1. Ter Stegen 3. Piqué 4. Rakitic 5. Sergio 6. Alves 8. Iniesta 9. Suárez 10. Messi 11. Neymar 14. Mascherano 18. Alba
Subs: 13. Bravo 17. Munir 20. Sergi Roberto 21. Adriano 22. Aleix Vidal 23. Vermaelen 24. Mathieu
Manager: Luis Enrique
Goals: 71′ & 80′ Messi,