Boro fell victim to a flurry of late goals at FC Heidenheim's Voith-Arena on Saturday.
After summer storms and a string of VAR interventions, the 2.Bundesliga side took control in a goal-filled last 20 minutes.
Crucially for many members of Boro's team, it was an extended stint on the field as pre-season preparations continue.
Take a look at photos from the game in the gallery above.
(Photo credit: Klaus Walz)