SUNDERLAND: Dixon, Marrs, Ferguson, Gorrin (Agnew, 72), Harrison, McNamee, Mitchell (Holland, 68), Laidler, Mandron, Smith, E Robson (T Robson, 70).
Smith’s 38th-minute penalty was enough to win the game.
The Black Cats started brightly and went close on five minutes, Adam Mitchell and Liam Marrs played a neat one-two before the latter crossed to the back post for Jordan Laidler, but he volleyed over.
Mikael Mandron then went close to breaking the deadlock on 11 minutes; the Frenchman saw his header saved by the Boro goalkeeper after a good cross from David Ferguson.
Boro nearly took the lead when Sunderland keeper Joel Dixon didn’t get enough on his clearance, but the stopper recovered in time to block Matthew Dolan’s stinging strike.
Smith then scored the only goal of the game seven minutes before half-time; he weaved his way into the area before being bundled over by Christian Burgess leaving the referee with no choice but to point to the spot.
Boro started the brighter in the second half and Cameron Park blazed over from six yards after Marcus Rhoden scuffed his shot.
The visitors’ best chance of an equaliser fell to Rafael Peireira, who volleyed wide after good play from Andre Bennett.
Sunderland could have doubled their advantage ten minutes from time but substitute Tom Robson’s shot was well saved by the Boro keeper after good interplay with Mikael Mandron.