The French World Cup victor had been in brilliant form for the Premier League champions prior to being sidelined by a foot injury for the past month.
They finished 25 points behind City in the league but the signs are it will be a much closer battle this season, with each team having only dropped two points from a possible 21.
'We got a little bit sloppy and complacent when Hearts had a man dismissed.
City were beaten 3-0 in that Champions League quarter-final first leg after conceding three times in the space of 19 minutes in the first half.
The former Atletico Madrid striker Aguero is now City's all-time goal scorer with 148 top-flight goals, 111 more than Salah, who has scored 37 in the Premier League so far; 35 with Liverpool and two with Chelsea.
Sure, it may all change in the next four or five games, but something tells me the top five or six will remain tightly bunched until December, at least. I know we are capable of it. At home, the performances are fantastic and the supporters really help the players. With the ball, again the timing was not good because we felt under pressure when there was no pressure.
The Premier League's two title favorites huffed and puffed but, ultimately, neither team was able to blow the house down at Anfield. If we don't entertain the people why are we playing then? On-loan Burnley defender Jimmy Dunne did head the visitors a consolation effort but they were already a man light by that point after seeing Michael Smith sent off early in the second period.
"But that would mean I forget completely how we played three days before against Chelsea, so we have to stay cool".
Manchester City's arrival at Anfield passed without incident ahead of their top-of-the-table Premier League fixture against Liverpool.
Sterling has received hostile receptions and struggled in games back at Anfield since leaving the Reds for City in 2015. Maurizio Sarri's side have perhaps been underestimated, but they - like both City and Liverpool - have 20 points on the board after eight games. We don't know in this moment as well if he can train tomorrow, we have to see. When somebody's telling me, "Good luck for Sunday", I think always, "Unfortunately, we need it".
Klopp was waiting to learn whether midfielder Naby Keita would be available after suffering a back spasm in Naples while forward Adam Lallana is back in full training following a groin problem.