Conor Wickham had threatened to spoil the party with his second half strike that looked like earning the home side a point.
But Toure, whose deflected effort put City in front in the first half, tapped home with seven minutes to go to secure a 2-1 win.
And he made an emphatic statement opening the scoring after 39 minutes.
Palace came out with renewed vigour in the second half – piling the pressure on City’s goal while Selhurst Park rocked.
With City staring down the barrell of a fourth draw in their last five Premier League games, Toure was on hand to tap over the line from six yards.