After the upset of the Carling Cup Final defeat, The Gunners had to pick themselves up, dust themselves down, and return to action against an Orient who had held them previously at Brisbane Road.
Wenger rang the changes handing a second start to the impressive Ignasi Miquel at centre back partnering Squillaci with Eboue and Gibbs protecting the recalled Almunia.
Arsenal started brightly, Diaby having a shot parried early on, and they looked the business, so the first goal came as no great surprise. Marouane Chamakh ending something of a goal drought turning in a cross from Tomas Rosicky after a decent run to the line and deft cross into his path.
The goal gave The O's a bit of a lift, and they showed just why they had earned themselves this replay crafting a couple of chances, one of which went narrowly wide, but the net bulged when the ball hit it from behind stirring the Orient fans into life as they thought the ball had gone in - I must confess to having a slight panic myself!
Arsenal took the pressure in their stride before Gibbs chipped a decent cross over and the start of the Bendtner show got under way and the striker powered a header past Jones in the Orient goal. Then a moment of brilliance as Rosicky pinched the ball, rolled it on to Bendtner who turned and curled a right footed shot into the far corner putting the Gunners 3-0 up.
Half time didn't stop Bendtner, Arsenal pushing and coming close until Gibbs was brought down in the box. Only one person was going to take the spot kick, and upstepped Nicklas Bendtner to power the ball home and in doing so became the first Arsenal player for a couple of decades to record an FA Cup hattrick. As Bendtner had made sure he was keeping the matchball, Wenger brought on fresh legs, and one pair of those, Gael Clichy had the task of finishing the rout after Chamakh let the ball run into his path, expertly drilling in from the left of the box.
Mission accomplished, albeit via a replay, and a ticket booked to Old Trafford in the last 8. Before that though, the small matter of Sunderland in the league and Barcelona in the Champions League, three games in three competitions that could well define the season.