The Teessiders trailed 2-1 in the tie after a tense first leg at Anfield. 

But two goals inside the first four minutes at a raucous Riverside turned the contest on its head. 

Mikkel Beck was tripped by Jamie Carragher and Paul Merson slammed home the spot kick, then Merson fed debutant Marco Branca to fire home through the legs of David James. 

It was enough for Boro to book a third Wembley trip in the space of a year.

Watch extended highlights from the game in the video player above.