Ashley Fletcher and Grant Hall completed their first 90 minutes since returning from injury in Sunday's U23s game against Leeds United.
The duo were joined by Jordan Archer, Hayden Coulson, and Djed Spence at Rockliffe as boss Neil Warnock cast an eye over proceedings.
Despite the experienced line-up, Boro were hit by a Leeds blitz that saw the visitors race into a four-goal lead before the half-hour.
Two goals from Joe Geldhart and one apiece for Nohan Kenneh and Max Dean put lively Leeds firmly in the ascendancy long before the half-time whistle.
Boro shaped up far better after the break, though, and Cain Sykes scored twice to give the score a more respectable look.
Ashley Fletcher and Coulson were both denied opportunities to reduce the arrears further as Leeds held firm to win 4-2.
The result gives Leeds a 12-point advantage at the top of the table while Boro are in ninth spot, five points behind second placed Reading.