It was only a fleeting spell, just 11 minutes, but it was enough to catch a glimpse of what Tottenham Hotspur should have looked like this season and what they can still be.
For in the second half in Belgrade, the moment Ryan Sessegnon came on to the pitch the Spurs fans were finally treated to the sight of all three of their summer signings playing on the pitch together.
Not only that, but for the first 62 minutes of the game the team was shorn of all those who had wanted or expected to leave Tottenham in the summer. Danny Rose was on the pitch but there's debate to be had over whether he actually wanted to exit the club or was pushed toward the door.
To see Tanguy Ndombele, Giovani Lo Celso and Sessegnon all pushing Tottenham forward, dovetailing and injecting fresh energy and belief into the team was how it should have been from day one this season.
Mauricio Pochettino's 'painful rebuild' was hampered from the first day of the campaign.
Sessegnon arrived with a hamstring injury, one that would take more than four months for him to fully recover from.
Lo Celso turned up at the club on deadline day without a pre-season to speak of and promptly picked up a hip injury on international duty which would rule him out for more than a month when he would have been established in the team. Even Ndombele missed three weeks through injury.
Only Tottenham Hotspur can ensure the rebuild is painful before it has even begun.
Mauricio Pochettino will have been heartened to see all of them out there at once finally.
Even with only two of them utilised from the start, this had been a vastly improved performance with more of the aggressive pressing and ball domination that Tottenham first became known for under the Argentine.
The pressing needs to happen as a pack. If one or two players are not doing their bit then the whole system breaks down.
It's a demanding tactic and for it to work, the manager needs everyone to buy into the idea.
For too long this season Pochettino has watched on as certain players have failed to implement the aggression he wants in the opposition half. That lack of enthusiasm is a natural by-product of moves away not gained, an overfamiliarity with the regime and to put it bluntly, staleness.
Pochettino has told football.london this season, even after performances where the pressing has been improved, that he wants more and that the team are not yet doing it as aggressively as he wants.
That's partly down to him as he's continuing to pick those players who are not carrying out his instructions and it's also because he knew he needed the infusion of young, eager minds ready to take on instructions that are new to them.
Pochettino noticed it even if he didn't single out the reasons why.
"We talked a lot with the players and we designed a plan to play and it was good to dominate and play in the opposition half, that was the idea," he said.
"The plan was to try to battle this atmosphere and energy and be in the opposite half with aggression on the ball, trying to dominate. I think that approach from the beginning was very good. We defended well and in the end we dominated.
"Our positional game in the opposition half was excellent from the team.
"We provided them with the ability to grow during the game with the atmosphere they were going to face here. I think it was fantastic, we have to keep going, it is only a very, very small step. But it is a step forward."
All three of the new signings bring with them a turn of pace, creativity and aggression in the tackle. They are also all versatile players who can operate in a number of positions. They're dream players for Pochettino.
It's no coincidence that they revelled in their minutes on Wednesday night.
Lo Celso ran the game in the final third for Spurs throughout his 85 minutes, always looking for the ball and getting it and his goal on his full debut was the epitome of calm amid a crazy penalty box scramble.
On his Champions League debut, Sessegnon showed the direct play he will bring, racing down the touchline, closing opponents down and getting to the byline before picking out Christian Eriksen to score Tottenham's fourth.
Then there is Ndombele. He's had slightly longer to adapt to Pochettino's ways and he now looks like a man who knows he can blow away most opponents on the pitch. His skill and close control is breathtaking at times.
Tottenham have their new Dembele, and this one can play a perfect final ball and even score goals.
There's still a long way to go though and Pochettino knows the trio still have to adapt to his methods and two of them to the English game.
"Now Giovani only needs time like Tanguy and Ryan Sessegnon," Pochettino told football.london .
"They are so young. They arrive now to the team in difficult circumstances, not the best circumstances. That is why like I tell you always I don't expect too much, I am happy with that they provide to the team. They need time. I am happy with the players."
So were the fans and if those few minutes are anything to go by, the future looks bright for Tottenham Hotspur as long as Pochettino just lets the new boys do their thing.
