SUBSTITUTE Haydon Hackney scored an 87th minute winner to complete a frustrating evening for the Brewers as they slipped to a 1-0 defeat in their final Checkatrade Trophy game of the season
The youngster glanced home a cross from fellow substitute Billal Brahimi with his first touch of the game to hit Albion with a sucker punch after they had dominated long spells of the game without managing to beat the experienced Andy Lonergan in the Boro goal.
Lonergan was much the busier of the two goalkeepers in terms of shot saving but Albion's finishing touch let them down although Jack Robinson had to head a Liam Boyce header off the line inside the last ten minutes after Nigel Clough had sent on his leading scorer along with Jamie Allen and Jake Hesketh in an attempt to secure victory.
For the final game in this season's competition for the Brewers there were a raft of changes as Will Miller got more minutes under his belt slotting in at right back with non-contract signing Kieran Wallace on the left with Damien McCrory and Jake Buxton forming the centre defence partnership in front of Dimitar Evtimov. Ben Fox, Joe Sbarra and Elliot Hodge made up a youthful midfield with Marvin Sordell operating as the central striker and Marcus Harness and David Templeton providing the threat from out wide.
Despite starting the game at full back it was Miller with the first meaningful attempt on the Middlesbrough goal with less than ninety seconds on the clock, a precise through ball the midfield picking out his forward run with Lonergan making a smart stop with an outstretched leg to keep the visitors on terms.
Albion continued to look the more purposeful and Hodge was next to test Lonergan after some excellent slick passing got him in beyond Sordell and in on goal, albeit, from a tight angle with the keeper safely cutting out the shot at his near post.
Middlesbrough looked tidy when they came forwards and Stephen Walker couldnt keep his effort down on 20 minutes after twisting and turning inside the box to evade the attentions of Wallace before lifting his shot well over the bar from an acute angle.
Walker was slightly closer with a centrally placed free kick just outside the box on 24 minutes after a combination of Fox and McCrory crudely halted the run of Tyrone O'Neill into the penalty area.
A Burton set-piece almost broke the deadlock on 33 minutes as Templeton whipped in a near post cross and Wallace got on the end of it to flash a header wide of Lonergan's upright rippling the side-netting in the process.
Marcus Harness went closest yet on 37 minutes after another swift Albion move saw the winger get in behind before cutting back and curling a left foot cross back across the keeper and narrowly missing the far post by inches.
Templeton's rasping drive from just outside the box forced Lonergan into an athletic save before Evtimov was forced to dash from his line to deny Kian Spence at the other end as the visitors showed plenty of pace to counter.
Half time: Burton Albion 0-0 Middlesbrough U21s
As in the first period it was Albion with an early chance to break the deadlock but this time Harness's deep cross finally found Templeton beyond the back post but he lifted a close range effort over the bar and the Scot was also guilty of not testing the keeper when Wallace's burst through the middle was halting allowing the former Hamilton man to set his sights from a temptingly positioned free kick.
The pattern from the first period was continuing into the second half as the Brewers continued to dominate large parts of the game without overly stretching Lonergan although Sordell's effort on the hour mark forced him into a meaningful save. Sbarra's rising effort from the edge of the box was also just too close to the keeper and Albion were almost made to pay a minute later, Dan Ward's snapshot flashing wide of Evtimov's post.
Ward then had Evtimov at full stretch with another effort from the left hand side of the box that took a deflection that took it wide of both keeper and goal. It was almost a case of third time lucky for Ward on 67 minutes, another shot this time thumping against the post.
With Jamie Allen having already come on for Templeton the final ten minutes saw Liam Boyce sent on in place of Hodge as Albion looked to avoid a penalty shoot-out. Boyce had only been on the pitch a couple of minutes when he watched on as Jack Robinson headed his goalbound effort off the line.
Jake Hesketh was also sent on late in the game in search of a goal but in the end it was a Middlesbrough substitute that won the day and gave the visitors their only win of this season's competition.