Wigan Athletic crashed to their fourth defeat in a row - all of them without scoring - with Britt Assombalonga's first-half goal on Teesside proving decisive.
Paul Cook's men suffered more away-day misery, despite starting the game in relatively positive fashion.
However, they were unable to make the most of their early work, and allowed Assombalonga a cheap goal on 23 minutes that ultimately proved decisive.
Latics were unable to muster much in the way of a response, and their night was summed up when Kieffer Moore was forced off in the closing stages through injury - with all three substitutions already made.
Sporting two changes from the weekend line-up - Jamal Lowe and Cedric Kipre for Michael Jacobs and the suspended Joe Williams - Latics quickly settled into their stride.
After a Boro mistake at the back, Gavin Massey played in Lowe, whose powerful shot was helped over the bar by Darren Randolph.
Latics were unable to test Randolph further, despite enjoying plenty of possession in good areas.
And they paid a high price when Jonny Howson's cross was headed home by Assombalonga.
The big Boro striker then forced a good save from David Marshall, with Paddy McNair firing wide from the follow up.
And a scramble in the Latics box from a Boro corner saw Sam Morsy hoof it away in the nick of time.
After Assombalonga fired wide again, Latics were grateful to hear the referee's whistle for half-time.
The visitors started the second period in bright fashion, with Moore heading wide from a Danny Fox cross.
Moore caused some anxiety on the Latics bench by staying down, holding his right arm, but he was able to continue.
At the other end, Ashley Fletcher advanced to the edge of the Latics box before firing wide of Marshall's left-hand post.
Latics boss Cook then tried to kickstart his side into life, bring off Massey and Antonee Robinson and sending on Kal Naismith and Bright Enobakhare.
Michael Jacobs took over from Lowe shortly after - and that third change was to prove costly for the visitors.
After Marshall again did well to save from McNair's header, Moore went down again in centre-field.
This time he was unable to continue, and Latics had to play out time with only 10 men - and unable to create one last chance.