Haaland reached 25 goals for the Premier League season with a hat-trick as City thrashed Wolves 3-0 in its most recent outing in the competition.
The Norwegian's fourth Premier League treble took him beyond the tally of 23 goals managed by last term's joint Golden Boot winners Mohamed Salah and Son Heung-min with 18 games of the campaign remaining.
Despite Haaland's exploits, Pep Guardiola's side trail league leaders Arsenal by five points having played an additional game, and City great Aguero says the striker cannot do it alone.
Asked whether Haaland can inspire City to a fifth league title in six seasons, Aguero said: "We'll have to see that yet.
"There's still plenty of the season to go. Haaland, who has been racking up numbers that will break historical records, will play a major part in it.
"In any case, except Leo, there's no one player who can win a league on their own.
"It's about the team, and City have got a very talented roster and exceptional staff. They've given plenty of evidence of their great stature, and you know they'll fight until the very end."
While City have struggled to keep pace with Arsenal so far this season, five-time Premier League winner Aguero remains confident Guardiola's men can overturn the Gunners' lead.
"I wouldn't say that Man City aren't clicking. The Premier League is the most competitive league there is," he continued.
"It's perfectly normal to see the top contenders get reinforcements and go back to their historical standards.
"City have won four out of the last five Premier Leagues. They're still in the fight, and that needs to be recognised. [They are] prowling from the second position, ready to strike. Anything can happen."
City will travel to Arsenal for the duo's first league meeting of the season on 16 February, after facing Tottenham and Aston Villa in its next two fixtures.