Sixty-eight minutes into Borussia Dortmund's home game against FC Ingolstadt 04 on Matchday 19, the vast majority of the 81 thousand-plus crowd at the Signal Iduna Park watched on in vague collective bemusement as a young substitute entered the fray for the hosts.

He may have played a key role in  the U-17s' march to the German title last season but Christian Pulisic was a completely unknown quantity at this level, even for many a BVB diehard. And now here he was, taking his professional bow in a game balanced on a knife-edge at 0-0 – the eighth-youngest Bundesliga debutant ever, at 17 years and 134 days old.

Having fun

If he was nervous, let alone anxious, the Pennsylvania native with Croatian roots didn't show it. Come the final whistle Dortmund had their three points in the bag, courtesy of a late Pierre-Emerick Aubameyang brace. Pulisic had impressed as well in his 22-minute run-out, demonstrating his pace and crossing ability down the left.

© imago / Eibner

“When the ball's at my foot, all I'm thinking about is the game,” he said afterwards; “The coach just told me – You've got to enjoy it. Have fun!'”Advice taken, Thomas Tuchel was duly satisfied with the start made by his young charge, saying,”He had a really great game.”

Just the beginning

The head coach had Pulisic and fellow midfield prodigy Felix Passlack training with the senior squad at BVB's winter training camp in Dubai. There, the US U-17 international – who as of this season had been starting for Dortmund's U-19s – evidently convinced Tuchel he was ready to make the step up.

His debut top-flight sampler off the bench was followed by two more in the subsequent games at Hertha Berlin (0-0) and against Hannover 96 (1-0). A first starting appearance is surely not far off now, for the Bundesliga's latest rising star.