Arsenal equalised moments later through Gibbs' header and young winger Oxlade-Chamberlain put the hosts ahead with a long-range shot that trickled past Shrewsbury goalkeeper Ben Smith.
That settled Arsenal's nerves and a first goal for on-loan Chelsea midfielder Benayoun killed the tie. At Elland Road, Michael Owen bagged a brace as Manchester United gained a measure of revenge for their shock FA Cup defeat against Leeds with a routine win.
Sir Alex Ferguson's team were left with red faces after Leeds, then languishng in League One, won 1-0 in the FA Cup third round at Old Trafford in January 2010.
But there was no repeat of that shock scoreline this time as Owen's double and a Ryan Giggs goal secured an emphatic success on United's first visit to Elland Road for eight years.
"Owen's ratio of goals to games is unbelievable and his second goal was fantastic," Ferguson said.
"With Berbatov, (Javier) Hernandez and (Wayne) Rooney around the place he's not getting the games he deserves. It's unfortunate for him, but he's fantastic to have around."
United were in front after 15 minutes when Owen converted Park Ji-Sung's pass.
Owen produced another cool finish for his second goal from Mame Diouf's cross in the 32nd minute and Giggs put the result beyond doubt with a fine individual effort on the stroke of half-time.
AFP