London: Arsene Wenger accused Arsenal of naivety after they were pushed to the brink of another frustrating Champions League exit by Lionel Messi's brace in Barcelona's 2-0 win at the Emirates Stadium.

Wenger was infuriated his players failed to heed his warning to keep it tight at all costs in the last 16, first leg on Tuesday as Messi punished the hosts' careless defending with a clinical 71st-minute opener. Messi then took advantage of a needless foul on him by Mathieu Flamini, stroking home the resulting penalty to leave Barca on the verge of reaching the quarter-finals for a ninth consecutive year.