Arsenal went a goal behind before a second half revival saw them go through 2-1 against West Ham at Upton Park. The Hammers were good value for their first half lead given to them by Alessandro Diamanti when he beat the Gunners offside trap in first-half injury time.
Arsenal improved after the break and Arsene Wenger's double substitution on 64 minutes of Abou Diaby and Samir Nasri proved a turning point.
Arsenal had not lost in the third round of the competition since 1996 and Aaron Ramsey ensured that record continued when he equalised with 12 minutes remaining.
Five minutes later and Arsenal were in the fourth round as Eduardo headed into the top corner from Carlos Vela's cross.
Keeper Robert Green seemed to react slowly to the header and will be disappointed with his efforts.
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