Boro were dealt a late blow as hosts Hull edged a scrappy encounter at the KCOM Stadium.
The Teessiders made the perfect start to the match with a goal inside the first five minutes.
Marvin Johnson unleashed a rasping drive from the left flank which was parried by goalkeeper George Long, and as Hayden Coulson looked set to dispatch on the rebound he was scythed to the floor.
Britt Assombalonga stepped up to take the spot kick, and dispatched it confidently into the top right corner.
But it was a lead the lasted even less time than it had taken Boro to build.
Johnson tussled with Mallik Wilks on the edge of Boro’s box, referee Geoff Eltringham adjudging a foul in the hosts’ favour. Herbie Kane set his sights from the angle of the area and curled beyond Dejan Stojanovic to level the scores.
After a blistering start the game failed to find a real rhythm - it was scrappy from both sides with the sound of the referee’s whistle issuing its shrill sound all too often around an empty KCOM Stadium.
Paddy McNair showed drive from midfield to escape the regimented Tigers defence, but poked his effort tamely off target.
Patrick Roberts and Djed Spence were lively down Boro’s right, the former drifting in onto his left foot before blazing over from the edge of the D. Spence unleashed his blistering speed on several occasions as the first half wore on, but Boro were unable to capitalise.
Spence was forced off with an injury in the early stages of the second half to be replaced by Lewis Wing, Jonny Howson dropping into right back, while Marcus Tavernier and Ashley Fletcher were also introduced as Boro sought the advantage.
Tavernier looked to repeat his efforts from last weekend’s match at Stoke, and wasn’t too far away with a rasping left-footed strike.
The Boro number 7 then had the ball in the net after getting behind the Hull backline, but was penalised for a foul.
The points were there to play for but Boro’s final ball lacked the quality to penetrate a stubborn defence.
And Boro were dealt a sickening blow when, deep in stoppage time, a free-kick was hoisted into our area at the second time of asking and Wilks prodded in the winner.