Aguero responded to his own six-game drought and City’s winless run with a quick fire double in the 19 and 28 minutes.
He opened the scoring with a low right-foot finish which fizzed under Baggies keeper Ben Foster after being played in by Ilkay Gundogan.
Then he seized on a mix-up in the home defence to snatch possession and rifle in an unstoppable shot on the turn from the edge of the area.
Albion, who were jeered off at the break, improved after the break but Gundogan got on the score sheet late on after Aguero turned provider. And the German snatched a second from a De Bruyne assist to get City back on track.