It was an afternoon to forget for Tony Philliskirk's youngsters, as the Clarets fell to a 4-1 defeat at Middlesbrough's Rockcliffe Hall Training Base.
Goals from Pharell Willis, Fenton John, Max Howells and Nathan Simpson gave the hosts a comfortable lead, before substitute George Walters fired in a late consolation goal for the visitors.
It was a competitive start on a gloomy afternoon in Darlington, with both sides pushing for the opene
But with 13 minutes played the deadlock was broken as Boro struck first, as Willis rifled the ball in from the edge of the area following a set-piece.
There was a great chance for the Clarets to level shortly after, as Sam Unwin broke through on goal, before seeing his effort saved by Hnery Popple in the Boro goal.
Middlesbrough then came close to adding a second with 10 minutes left of the first-half, as Willis stole the ball from Rooney, before striking it against the post.
However, just before the break Boro did double their lead. This time, as midfielder John slotted into the bottom corner from close range past Sam Waller.
Philliskirk's side came out on the front-foot in the second-half and pushed to get themselves back into the game, with a change of formation and a shift in style.
But it was the hosts who struck once again, as Howells pounced on a loose ball inside the area and fired home to put the game out of reach with 20 minutes to go.
Just three minutes later, Boro added a fourth, as substitute Simpson finished a counter-attack and rubbed salt in the wounds on a difficult afternoon for the Clarets, who did pull a goal back in the last minute, as Unwin broke down the left, before picking out Walters to tap in from close range.
BURNLEY: Waller, Coppack, Ward (Leckie 53), Rooney, Armstrong, Trialist, Ratchford (Eastmond 80), Hugill, Behan (Walters 75), Unwin, McGlynn.
Subs: Sassi, McCullough.