Ashley Fletcher and Harry Chapman were both on target but Boro were beaten 3-2 by Rochdale at the Crown Oil Arena in the latest pre-season friendly.
As promised, Tony Pulis rang the changes after Saturday’s game at Accrington to allow more of his squad to get some game time, and Grant Leadbitter captained a youthful side.
And it took just 13 minutes for Boro to take the lead with the first real chance of the game. Lewis Wing did well to keep the ball in play down the left hand touchline before picking out an unmarked Fletcher who headed home with ease.
Defensively, both Dael Fry and Nathan Wood made a couple of good headed clearances, while Harry Chapman sent a shot over the Rochdale bar after breaking quickly. Britt Assombalonga also forced Josh Lillis into make a good save - via the woodwork - after another incisive break by Boro.
Assombalonga was also called upon at the other end when he made a goal-line clearance to deny Calvin Andrew from a corner after a brief spell of Rochdale pressure. Wood also made another great block shortly before half-time to deny Jordan Williams what would have been a certain goal.
It was Boro who almost furthered the advantage early in the second half, but Lillis spread himself well to deny Assombalonga.
Moments later, it was 2-0. Fletcher picked out Chapman with a lovely cross-field ball and the youngster advanced before driving a low shot into the far corner.
Substitute Connor Ripley was called upon for the first time on the hour mark when he had to react well to block an effort from Joseph Thompson, while Marvin Johnson also did well to cut out a cross which could have caused problems for Boro.
The home side did pull a goal back on 68 minutes, though, when veteran striker Calvin Andrew got up well to head home a cross from the Rochdale right.
There was a flurry of substitutions as the game ticked on and one of those, Alex Pattison, made Lillis work when he drilled a shot goalwards after good work by Johnson and Callum Cooke.
But honours were even after Bradden Inman was the beneficiary of a fortuitous ball into the box and was able to convert from close range.
And in the dying seconds, despite a stunning initial save from Connor Ripley, Oliver Rathbone was able to scramble home a late winner for the home side.
Rochdale: Lillis, Ntlhe, McGahey, Williams, Andrew, Williams, Thompson, Perkins, Adshead, Cannon, Henderson. Subs: Rafferty, McNulty, Camps, Rathbone, Wilbraham, Inman, Finnerty, Morley, Wade, Gillan.
Boro: Konstantopoulos (Ripley 46), Mahmutovic, Wood, Fry, Johnson, Leadbitter, De Sart (Liddle 81), Wing (Pattison 67) Fletcher (Walker 74), Chapman (Cooke 60), Assombalonga (Spence 80). Subs: Braithwaite.
Referee: G Salisbury
Att: 909 (174 Boro)