Middlesbrough have come out on top in the Wear-Tees derby at the Stadium of Light to progress to the fifth round of the Capital One Cup.
The Black Cats came closest to breaking the deadlock early on when Adam Johnson let fly from a tight angle but was kept out by Jason Steele.
Middlesbrough were seeing plenty of the ball against an experienced Sunderland XI and Scott McDonald shaved the top of the crossbar with a clipped effort on the half-hour mark.
John O'Shea just headed wide for Sunderland before Boro took the lead six minutes before the interval through McDonald, who nicked in at the front post to flick home Ishmael Miller's centre.
Sunderland dominated possession for the remainder but rarely troubled Steele. Stephane Sessegnon created the best opening with a darting run but couldn't apply the finish as he flashed wide.
The draw for the fifth round takes place tomorrow night.
