Boro's Under-18s were denied the chance to retake top spot in the Premier League North by visiting Manchester United.
Mark Tinkler's youngsters had lost just once this season heading into the Rockliffe match-up, but it was United who came away with victory, closing the gap between the sides to a point and preserving neighbouring Manchester City's spot at the top of the table.
A scruffy effort from in-form striker Joe Hugill put United ahead inside the first three minutes, and set the tone for a frustrating Boro afternoon.
Tinkler's young charges were dogged in their pursuit of a way back into the contest, pressing high and penning the visitors in for long periods. Striker Josh Coburn was thwarted by a last-ditch tackle as he streaked through on goal, then Pharrell Willis was denied a penalty in the closing moments of the first half.
Despite the home side looking the more likely to add to the scoresheet, it was United who doubled up their advantage when Hugull tucked home his second of the game just before the hour mark.
By now the travelling team were taking control, and it would be three just minutes later as Charlie Wellens swept home at the end of a flowing move.
Willis gave Boro a glimmer of hope when he found a way past Johan Guadagno with nine minutes remaining, and for a fleeting moment it looked like the Teessiders might make a go of it as Coburn and Calum Kavanagh both went close.
But the Red Devils had the final say, substitute Isak Hansen-Aaroen ghosting in to add gloss to the win with a fourth goal in stoppage time.