LONDON -- For 25 minutes Tuesday, Ajax appeared to be playing a different sport to Tottenham Hotspur.
Their superiority was such, their passing so quick, their thoughts so clear, that if you'd offered most Spurs fans a 3-0 defeat after the first quarter of the game, plenty would have taken it. Spurs played as if they had been spun round a dozen times before they emerged onto the pitch, dazed and unsteady. Ajax made 132 accurate passes in the first 15 minutes. Spurs had 43.
"For the first 20 minutes we were just ball-watchers," Christian Eriksen said after the game.
So in the end a 1-0 defeat turned out to be a relatively decent result. When Donny van de Beek had the penalty area to himself in the 15th minute, sat Hugo Lloris down and passed the ball into the corner of the net, it seemed utterly implausible that it would be the only Ajax goal of the night.
Ajax had sliced through the Spurs defence with such ease, Van de Beek finding himself in so much space because the home side almost looked hypnotised by the passing and movement in front of them that it seemed to slip their mind to mark him.
"The way we conceded the goal was so painful," Spurs manager Mauricio Pochettino said, genuinely looking in pain as he spoke.
Spurs looked utterly suffocated. At one stage, Victor Wanyama tried to bring ball out of defence but was immediately set upon by three Ajax players and relieved of possession before he could even think about starting an attack. It was like a trio of velociraptors jumping on a lumbering stegosaurus.
And yet, it might turn out to be enormously costly for Erik ten Hag's side that they didn't score a second in this period of dominance. After that opening salvo, they almost seemed to back off, either because no mortals could keep that pace up for longer, or they perhaps loosely assumed they were so much better than Spurs that the result of both match and tie was inevitable.
Afterward, Ten Hag conceded that his team could and should have made more of their initial superiority, also admitting that his team "did not anticipate" Tottenham's change in approach, their more direct and physical style.
Perhaps we should give Spurs more credit for the shift in the game. Pochettino switched formations after about 20 minutes, moving Danny Rose into midfield, and then Jan Vertonghen's horrible-looking injury -- knees buckling when he was initially allowed to return to the pitch, after his nose ploughed into the back of Toby Alderweireld's head -- actually turned out to be, from a tactical perspective at least, a positive.
Moussa Sissoko changed a Champions League semifinal. For his side. For the better. Lots of strange things have happened in the world in the past few years, but that's among the more curious. Or, more accurately, would have been curious nine months ago. Sissoko's influence faded in the latter stages of the game, but his initial impact after replacing Vertonghen allowed Spurs to take more control of midfield, and to play in that more direct manner that Ten Hag didn't expect.
Spurs decided that the way to stop Ajax was to plug the holes in midfield, which Sissoko helped with hugely, and then aim as many crosses as possible at Fernando Llorente. There's no shame in that: You win games of football by being better than your opponent at the things you're good at. It's no good trying to compete with the things they're good at, just for the sake of it.
After the game, it felt slightly curious that Pochettino seemed to strike a more positive tone than Ten Hag.
"It's a very good starting point, but we have to learn lessons from this game -- we must do better next week," said the Ajax boss, while Pochettino accentuated the positives of the second half.
This was one manager relieved that Tottenham were still in the tie and another slightly dissatisfied that they hadn't been finished off. David Neres hit the post in the second half and Ajax had a few other half-chances, but ultimately a 1-0 victory was a disappointment after that opening half-hour.
The question now is what this means for the second leg. Spurs will have Son Heung-Min back and Sissoko perhaps available from the start. The way they wrested at least some control back in the final hour, even if they ultimately struggled to create chances, both kept them in the game and indicated that they are more than capable of getting a result in Amsterdam on May 8.
They need to win there, though, something they haven't done much on their travels lately. The bad news is that Spurs have won only one away game since January. The good news is that was at Borussia Dortmund.
"We are still alive," Pochettino said. "The second half gave us the hope for the second leg."
Hope looked like a very distant thing in the first 30 minutes, but they've got enough to cling to.