In the aftermath of Dortmund's aggregate victory over Real Madrid, concerns were raised over the No. 10 position in Juergen Klopp's side.
Mario Goetze limped off early on with a hamstring issue, giving the boss a serious problem: How do you replace a player of that quality in such an important position?
In the immediacy, Marco Reus filled in at the Santiago Bernabeu and acquitted himself nicely, while jack-of-all-trades Kevin Grosskreutz took Reus' place on the left.
I analysed that choice and asked whether Reus was the future—either long-term or in the UEFA Champions League final—and several astute B/R commenters pointed to the possibility of Ilkay Gundogan filling that role.
Klopp had the very same idea, and trialed Gundogan in the position in a test-run against Bayern Munich on Saturday.
The German moved to Dortmund from Nuremburg in 2011 having played as an attacking midfielder behind striker Julian Schieber, and it was Klopp who moved him back into a No. 6 role.
He's become a true defensive presence for BVB after retraining for a deeper position, and initially looked a little uncomfortable floating between the lines.
He was tracking well and looking to tackle opportunistically, but failing to find himself space between the holding midfielders and forcing longer passes to Robert Lewandowski from the back line.
But after the first 10 minutes he kicked into gear, and in the 13th minute played a superb one-two and surged into the box. He took Diego Contento completely out of the equation positionally, and stand-in left-back opted to push Gundogan over in an attempt to recover.
It should have been a penalty and, subsequently, a real booster in Klopp's experiment. Instead, the challenge aggravated a pre-existing knock Ilkay was carrying, and he was substituted off in a precautionary measure.
On came Moritz Leitner, and while he is a youth product the world is desperate to see given more minutes, he has no chance of starting the final at Wembley.
And so Klopp's second chance to find a fit for the No. 10 role in his 4-2-3-1 formation ended badly, and we're still no closer to knowing what he will do should Goetze not make the final.
Gundogan was just settling into his former role and showing flashes of ability, and while the substitution was the right thing to do, Klopp will feel a little aghast at his run of bad luck.