This will be one of those Champions League nights when Pep Guardiola's every call is questioned, and while many of his pre-match selections were injury enforced, he will now have to come up with some answers if Manchester City are to reach the Champions League semi-finals.
That is because Tottenham, backed by a ferocious crowd in their new stadium, battled long enough and hard enough to earn a narrow 1-0 victory, courtesy of Heung-Min Son's late strike.
Guardiola is never far away from questions about his approach in big games. Of course, when his unorthodox line-ups are successful, it is soon forgotten that he had mixed things up in the first place.
And it would be foolish to be too critical of the Catalan at this juncture, given what he has achieved with this City side since the start of last season, not to mention the fact that this would have all been different had Sergio Aguero converted an early penalty.
In the event the Argentine's effort was saved by Hugo Lloris, and on such fine margins big games, big ties, are decided.
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City were not their usual attacking selves but they never set out to be. Guardiola respected Spurs and perhaps that will be scrutinised, too, but it was clear that he did not want his team to be too open, which has been his undoing in European competition at both Bayern Munich and City. And when he has set up like that and been defeated, he has been reminded of his mistakes very quickly.
With Bernardo Silva suffering a slight muscle injury, Guardiola plumped for Riyad Mahrez, who has hardly set the world alight since his move from Leicester last summer.
And with Benjamin Mendy out of the squad despite starting at Wembley on Saturday, Guardiola decided not to move Aymeric Laporte to left-back, where he has had mixed success, and instead chose Fabian Delph, who many suspected had played his last game for the club after some rash mistakes in his recent outings.
Mahrez was clearly sent out with the brief to play from deep and track back, which presumably Leroy Sane was not trusted to do to similar effect.
Ilkay Gundogan started instead of Kevin De Bruyne, who has also been fighting fitness problems, and his deep role alongside Fernandinho also ensured this would be a tight game.
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And had Aguero scored his penalty, City may well have won it. The striker has got lucky with a couple of recent efforts, namely when he hit the post at Swansea but the rebound went in off the goalkeeper, and at the Carabao Cup final at Wembley when the villain Kepa jumped over his bobbly strike.
But even with both of those he aimed low into the corner, as he usually does. Here, for whatever reason he went higher, into “good height for a goalkeeper" territory. Lloris palmed the ball away and the home fans roared. Aguero has now missed more penalties than anyone in the Champions League since his debut in the competition in 2008-09.
It was a close game after that, full of aerial duels and robust tackles. One of those could prove crucial, in fact. Harry Kane, who had battled with City's centre-backs as well as anybody, went in strong and late on Delph, and ended up rolling his ankle. That could well keep him out of the second leg and that will no doubt be a huge boost for City.
But the fact is that Spurs scored after Kane went off, and they have generally coped well without him this season. Still, City will need all the boosts they can get. A goalless draw would have been precarious enough, given a score draw would send Spurs through, but a 1-0 deficit leaves no room for error.
That deficit came courtesy of Son, who ran in behind Delph and, by keeping the ball in play, immediately got the upper hand on the jumpy converted left-back. The South Korean made a move back inside, feinted to fool Delph, and then used the extra space to fire off a low shot that Ederson, who had earlier damaged his hip in a heavy fall, allowed to go through him.
A squad is only as strong as its weakest members and while City's are hardly competition winners, Delph at left-back is probably as 'weak' as City get. He did not commit a heinous error, and in fairness any of City's other left-backs are more than capable of being caught out in the space behind them, but he did not cover himself in glory either.
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Moments like that, and of course the penalty, are what Guardiola keeps going back to when he discusses the difference between success and failure in this competition.
City had another 10 minutes to nick an away goal after that but Guardiola left it peculiarly late to bring on Sane and, especially, De Bruyne.
David Silva was not as precise on the ball as he is at his best and De Bruyne had looked an obvious replacement as early as half-time, but he and Sane were only introduced in the 89th minute. It was as if Guardiola had suddenly realised they were on his bench.
In the end they could not make a telling impact, their contributions in the final third as wayward as their team-mates'. Spurs continued to battle brilliantly and held on to what could be a precious advantage.
City are by no means out of this, and you would always back them to win at the Etihad Stadium, no matter who the opponent is.
Guardiola has a week to come up with the answers.