For all that there's still a glimmer, for all the early threat from Jadon Sancho, and for all the overachievement: the lack of a ruthless, game-stretching presence up front — and a worrying recent tendency to crumble in adversity — leaves Borussia Dortmund all but out of the Champions League.

Both sides came into Wednesday’s game without some of their most reliable threats, with Dortmund missing Paco Alcacer and Marco Reus and Spurs having lost Harry Kane and Dele Alli to injury. While Dortmund struggled to replace their cutting edge, in Son Heung-min, Spurs have a razor blade that seems to get sharper by the week.

“He’s been fantastic. He’s a player that provides the team a lot of very good things," said Spurs boss Mauricio Pochettino after the match. "He has good energy and the performances are improving and improving. We are so happy, it is so obvious how (important) he is."

After a first half where the Bundesliga leaders matched their hosts blow-for-blow as the swathe of yellow-and-black-clad fans beat a ferocious rhythm, it was the lethal South Korean who made the first, decisive cut in what would eventually become a near-fatal wound. Just after the break, Achraf Hakimi coughed up possession and Jan Vertonghen whipped in a cross that begged to be finished. Son, for the ninth time in ten games against the Yellow and Blacks, obliged.

Falling away

As in their 3-3 draw with Hoffenheim at the weekend, the first concession broke Dortmund’s resolve worryingly quickly. An even contest became one-way traffic, with Vertonghen doing a passable impression of Son for the second goal and 1.95m target man Fernando Llorente inexplicably left unmarked in the six-yard box from a corner for the third. The two strikes came in six late second-half minutes.

"We played well in the first half but the goal a minute after the break was a gift," said BVB coach Lucien Favre after the game. "After that, we played too hastily and it was hard to create chances."

Though they too struggled early on without their focal point, that was less of a problem for Spurs. Pochettino opted to play Son, his quickest, most direct and most potent threat through the middle. He may not be a completely natural fit for the role vacated by Kane, but the South Korean constantly asks questions of players on the last line of defense.

They were questions Dortmund’s patched up backline just couldn’t answer. Ömer Toprak was almost visibly shaking off the rust, constantly looking over his shoulder for Son like a nervous learner driver reverse parking into a tight spot with rush hour traffic building. Dan Axel Zagadou and Achraf Hakimi were not much better.

Dortmund’s threat was at first a little more subtle, before fading to the point where it was difficult to identify. Mario Götze was nominally tasked with leading the line but couldn’t ignore his natural desire to drop deep and find the ball. His best work was done from there, linking up play with Pulisic and Sancho bombing past but the pair were often too wide to make a difference and lacking a central target

Depth a major concern

Squad depth has long been considered a weak spot for Spurs, who have failed to sign a first-team player in either of the last two transfer windows, but it was Dortmund’s inability to cover their missing men that truly proved critical.

As the game entered its last quarter and the home side’s threat looked more ominous, heads turned towards Favre, who has so often been able to throw on Alcacer, or even Sancho, to swing a game. Not on Wednesday. Injuries meant the Swiss coach’s first change was to remove one defender for another. He was out of options.

For all Wembley’s size and grandeur, it's not always been a happy temporary home for Spurs. But the roar that followed Llorente's goal, one of a handful of occasions when the visiting fans were drowned out, suggests they'll at least have a few fond memories of the place to look back on when they eventually return home.

For Dortmund, it was another loss at England's national stadium. Though it was not as painful as their Champions League final loss six years ago at the same ground, it was a sobering lesson for a side now without a win in four and showing signs of wobbling after a half season of winning serenity. Favre will hope it’s nothing more than that.