The Os endeavours were rewarded with an 89^th-minute equaliser by substitute and late goal specialist Jonathan Tehoue after Arsenal had dominated long spells without creating many clear-cut chances.

Gunners manager Arsene Wenger fielded a strong side but an even stronger bench, which might have been utilised had the hosts scored earlier.

However, Tehoue’s right-foot strike from the edge of the box, after quick feet took him between two Arsenal defenders, came too late for Arsenal to retrieve the situation.

Arsenal created all the chances against the hard-working Os in a tight first half. Marouane Chamakh missed the best of them on 35 minutes, failing to properly connect with Kieron Gibbs’ left-wing cross when in front of goal, seven yards out.

But Arsenal led within eight minutes of the restart, Tomas Rosicky heading home Niklas Bendtner’s cross from the right flank from fully 15 yards.

Os keeper Jamie Jones saved another Rosicky effort on 68 minutes and also blocked the rebound from the Czech international before Orient’s persistence found its late reward.

The winners of the tie will visit Manchester United in the quarter-finals.