Tottenham were cast six points adrift of the Group B leaders after they lost 4-2 at home to Barcelona in the Champions League on Wednesday.
Philippe Coutinho and Ivan Rakitic scored in the first half before Lionel Messi took over after the interval and netted a brace to leave Spurs in desperate need of a win when they face PSV in Eindhoven three weeks from now.
Here are three things we learned from a richly entertaining evening at Wembley.
1. Messi Is Still the Best in the World
According to the results of the recent Best FIFA Football Awards, Lionel Messi is now the fifth best player in the world. If that were actually true then the four above him would have to be gods because Messi is not of this earth, as he showed again on Wednesday.
From the moment his instinctive cross-field ball found Jordi Alba in the second minute, it was clear that the Argentine was in the mood. He played a part in Barcelona's first two goals, hit the post twice early in the second half, and eventually got on the score sheet when he started and finished the best move of the night to make it 3-1.
Messi added another to make sure of the three points in the final minute as Tottenham were eventually forced to surrender. This was the sort of majestic performance which first established Messi as the world's best and showed that he is still at the top of his game all these years later.
2. Injuries Proved Costly for Spurs
A lot was made before the match of this being a good time to play Barcelona because of their three-game winless run, but injuries meant that this was far from an opportune time for Mauricio Pochettino's men to be facing one of Europe's most dangerous teams.
The influence of Dele Alli and Christian Eriksen was missed in the final third as Spurs struggled to create chances, particularly in the first half, while Mousa Dembele's absence was also keenly felt as Harry Winks and Vincent Wanyama failed to stem the Barcelona tide.
Perhaps the biggest miss of all was Jan Vertonghen, without whom Tottenham's defence looked all at sea. Pochettino will be pleased that there is an international break after this weekend, giving his injured players ample recovery time.
3. Arthur Could Spearhead Barca's Next Generation
Most of Barcelona's team are household names but one you may be less familiar with is Arthur. A summer signing from Gremio, he started alongside Ivan Rakitic at Wembley, making just his second start in Barcelona colours.
Yet on the basis of this performance, you would have thought Arthur had been at the Nou Camp as long as any of his teammates. He and Rakitic were so quick and decisive with the ball, setting a tempo which Tottenham couldn't cope with. The best compliment is that Xavi would have been proud of this display.
A lot of Barcelona's players, brilliant though they still are, are getting on in years. Busquets and Rakitic are 30; Messi and Suarez are 31. At the age of just 22, Arthur has years ahead of him in which to become a world-class player. Judging by this, it won't take him long.