The winger helped City to a 4-1 win at the Vitality Stadium to close the gap to Arsenal at the top of the league.
And the England star could not help but rub salt in the wounds of the Cherries fans after being substituted.
Grealish was forced to walk around the pitch so had to pass the Bournemouth fans on his way back to the dugout.
And he cheekily decided to wind them up by putting up the 4-0 scoreline on his fingers.
Fans on social media loved the trolling and many praised the “s***housery” on display.
One supporter wrote: “Grealish such a s***house I’m choking.”
Another added: “He’s a s***houser and we LOVE IT.”
And a third said: “He grows on me every week, we’ve signed an absolute diamond🤣”
Another commented: “Grealish lad I f***ing love him 😂”
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Another clip showed Grealish telling a Bournemouth fan to calm down as he shouted from the sidelines.
Grealish has enjoyed a run in the City team in recent weeks and has started the last nine games, producing one goal and two assists in that time.