COMMENT: It is faintly ridiculous to suggest a team that has scored 45 goals in 15 league matches has a problem in attack but the fact is Manchester City's defeat at Chelsea highlighted one thing: they need Sergio Aguero.
With Kevin De Bruyne injured, there has been a discussion asto which player is most important to the Premier League champions.
The current conclusion has been Fernandinho, given the Brazilian's unique role and that there is not a similar understudy should he, at 33, suffer an injury. Maybe it is David Silva, but for all the Spaniard's brilliance and the fact City are a better, slicker side with him, there are reliable options.
But at centre forward? Right now, the injured Aguero is irreplaceable and not least because Gabriel Jesus is struggling to such an extent that Pep Guardiola deemed he would start Raheem Sterling through the middle at Chelsea, although he later deployed Riyad Mahrez there.
Sterling did not play badly, although Mahrez and, on the other flank, Leroy Sane did. It is hard to envisage Aguero not taking one or two of the chances City spurned in a first 44 minutes of such utter dominance that they appeared to be on a different level.
Guardiola has played Sterling in that role in the past. He has even used Bernardo Silva there but Aguero was missed against Chelsea. Not just because of his individual chance conversion rate but because of the overall effect of him being in the team.
Aguero has eight goals in 13 league appearances this season but, crucially, with him in the side, City's conversion rate is 15.69 per cent, second only behind Arsenal in the Premier League.
Without Aguero, City are at 11.11 per cent, which puts them below Brighton, West Ham and Bournemouth, along with the other five of the 'Big Six'.
The good news for City is that Aguero is expected to be fit for Sunday's home game against Everton.
The other good news for City is that despite losing to Chelsea, in their opening eight away games, they have played Arsenal, Tottenham, Liverpool and have now been to Stamford Bridge. Of the 'Big Six', they have only to travel to Manchester United.
The good news for everyone (bar City fans) is that after Guardiola's first league defeat of the season, it appears there will be a title race, even if the holders remain clear favourites.
Liverpool are top and in that fight. Can Chelsea force their way in? Probably not.
City did not play poorly. They were sublime in the first half but they did miss Aguero. It is the kind of comment that infuriates managers, not least Guardiola. "Nobody knows," he said when asked whether his team would not have lost with the striker.
And of course he is right. It is hypothetical. But there is a weight of evidence.