City moved to provisional second, a point behind Leicester. But both could be overtaken by Arsenal, which was playing its 22nd-round match on Sunday at Stoke.Fabian Delph and Aguero, in the first half, relieved City's goal-scoring frustration after the scoreless draw with Everton on Wednesday. Aguero finished off a team goal for his second after more than an hour, and set up David Silva instead of going for his third goal.
"The first half, the two goals gave us more space, as they had to go for the draw," City manager Manuel Pellegrini said. "That allowed us to use that space and score two more."
Palace was without a win, or goal, in its last five league games, for the first time since 1988.
Delph's opener came out of nowhere, his long-range shot too low for Palace goalkeeper Wayne Hennessey to keep out.
Aguero added the second just before the interval, needing a big deflection off Scott Dann's head to deceive Hennessey.
After City suffered another injury blow, when Aleksandar Kolarov clutched his calf and had to be carried off, the team produced a special third goal. Aguero and Silva combined, Yaya Toure played Kevin De Bruyne into space on the right, and the latter crossed to give Aguero a tap-in.
De Bruyne has 11 assists to go with 11 goals in 29 matches in all competitions this season.
With time nearly up, City counterattacked and de Bruyne released Aguero from inside their half. He outpaced the defense to tee up an easy finish for Silva.
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