Manchester City shot to the top of the Premiership after a 2-1 defeat over Sunderland on Tuesday.
Goals came from England internationals Darius Vassell and Trevor Sinclair in the first half.
Anthony Le Tallac did score for Mick McCarthy's side, but it wasn't enough to stop the Black Cats' third Premiership loss in a row.
In other matches, Boro beat Birmingham 3-0 at St Andrews, and Portsmouth drew 1-1 with Aston Villa.
Birmingham 0-3 Middlesbrough
Mark Viduka scored twice in Boro's away match after 14 and 45 minutes.
Then Franck Queudrue made it three with his free-kick after 71 minutes.
Portsmouth 1-1 Aston Villa
Villa went ahead after just 11 minutes, despite having just been reduced to 10 men when Nolberto Solano was sent off for elbowing Richard Hughes.
But Lomana LuaLua equalised for Pompey after 42 minutes.