A goal from Pierre-Emerick Aubameyang and a brace from Marco Reus helped the Bundesliga giants secure a 3-0 win ahead of the second leg next Thursday. But rather than get too downhearted about the defeat, Mason has encouraged his teammates to try and use the loss productively and hinted that Dortmund should be a side that they aspiring to emulate.
"It has to be a learning curve. We want to progress as a team and play in the Champions League and these are the sort of teams we’ll come up against," he told the London Evening Standard.
"Dortmund are a top European side. They've shown that over the last four or five seasons. They're a Champions League-quality side and they'd do well in that competition this year."
While the nature of the defeat would have obviously been hugely disappointing to Mauricio Pochettino and the fans that travelled to the Westfalenstadion for the game, Spurs arguably have bigger priorities than the competition which appears to have inspired the manager's team selection.
Pochettino made seven changes from the team that started the North London derby with Arsenal, seemingly in the hope of keeping some of his key players fresh for the trip to face Aston Villa this weekend.
And if the squad rotation proves to be beneficial to their chances of catching Premier League leaders Leicester City, and, as Mason says, helps the young squad learn a thing or two about what it takes to compete on the continental stage, then the defeat will surely seem a lot less crushing than it probably does right now.