And while the Ligue 1 leaders gave the Etihad Stadium outfit a heart attack last time out, the end-to-end affair was sure to have entertained neutrals across the world.
And Pep Guardiola was not a happy man.
His strike-rate was never the issue.
Up to 18 players' futures are on the line, it said, as the owners are set to hand Guardiola at least £150 million (S$258.7m) to recruit new blood.
Watching from the sidelines has given Aguero the chance to see what is expected.
"The Man City team were obviously a top side, and arguably had more standout individual players".
Monaco and Atletico Madrid became the latest UEFA Champions League quarterfinalists after eliminating their respective opponents, Manchester City and Bayer Leverkusen, in the return leg of the last 16 on Wednesday. "Even in the first leg, City had a bit of luck". So I always feel he is there, so close to the team, so close to me.
Klopp has warned his squad they can not afford to be passive at the Etihad Stadium on Sunday or they risk being bypassed by City's ball players and so the plan is likely to be to go on the attack.
If he's out, that will be a huge plus. We conceded six goals over two games.
"Chances where you arrive at the byline and with one pass you score a goal, but we missed those chances".
If Vincent Kompany was fit, Stones would be having a totally different season to the one he is now. But he knows, I know better than him, how it works. What do you think? "And to achieve titles, that is what you have to improve".
These nights are major.
But the main focus is on out-of-favor or ageing players leaving the club, with seven regular players out of contract in July 2017.
He needs to do it consistently, though, not just one match, which has been part of his problem.
"Coming here, it's the most hard league in the world", Klopp began.
"We forgot to be there in the first 45 minutes", Guardiola, who could not hide his frustration on the touchline, said. "When you attack good, you defend good", he said.
With Aguero supported by Raheem Sterling, who has been directly involved in 10 goals across his last nine Champions League starts, the hosts genuinely look capable of outscoring any of Europe's elite.
City struggled to gain possession, made little use of the ball they did get and failed to repel Monaco's continual raids. If I was still playing, I'd be anxious about the speed they possess.
Coach Leonardo Jardim hailed another fine showing against Premier League opposition after knocking out Arsenal in 2015 and twice beating Tottenham in this season's group stage.