Pep Guardiola's side is on the brink of a third championship in four seasons but could not complete the job at Etihad Stadium after Sergio Aguero allowed Edouard Mendy to save a tame spot-kick.

That effort would have added a swift second to Raheem Sterling's breakthrough strike on the stroke of half-time.

Instead, Chelsea rallied after the interval and scored through Hakim Ziyech – its FA Cup semi-final hero against City – and then, in the final seconds, Marcos Alonso, to boost its top-four aspirations and keep the leader waiting, unable yet to turn its focus to the European showpiece.

Although Guardiola's puzzling 3-3-4 formation initially had Chelsea on the back foot, it was a defensive mishap rather than a tactical manoeuvre that forged the opening on 44 minutes.

Andreas Christensen misjudged a bouncing ball and was brushed aside by Gabriel Jesus, who squared for Aguero in front of an open goal, only for Sterling to sweep into the net when his team-mate dallied.

Aguero did not have to wait long for his next chance, as Christensen hobbled off and Jesus tangled with Billy Gilmour before Chelsea were able to introduce a substitute, prompting a City penalty.

However, as Thomas Tuchel fumed at the officials, a dreadful Panenka attempt from Aguero was gathered by Mendy.

The shortcomings of the City system were then laid bare shortly after the hour mark when Rodri – its sole central midfielder – lost out to Ziyech and left space for a Chelsea attack which ended with the same man arrowing a low finish beyond Ederson.

Chelsea pushed for a winner but was twice denied by the offside flag. Timo Werner had already strayed before netting in the first half and did so again, before a closer call kept substitute Callum Hudson-Odoi off the scoresheet.

City furiously appealed for a second penalty when Sterling went down under pressure from Kurt Zouma, but the final twist was in Chelsea's favour as Alonso's scuffed shot looped over Ederson.