Blues boss Alex McLeish had decided to split his squad into two groups with another friendly against Forest Green on Sunday.
There was however a first start for new signing Marcus Bent at the Priestfield Stadium.
Blues completely dominated the first half of the game and should have gone ahead as early as the 6th minute when Martin Taylor missed a glorious chance, the central defender headed wide when completely unchallenged from a Seb Larsson corner.
Blues did take the lead on 12 minutes when Cameron Jerome latched onto a defensive error which allowed him a one-on-one with the Gills keeper Simon Royce. Jerome made no mistake with a well hit shot from about 12 yards out.
Taylor made ammends for his earlier miss when he doubled the lead on 21 minutes. The giant centre-back played a nice one-two with Jerome and when the Blues strikers shot was parried out to Taylor he neatly slotted the ball past a helpless Royce.
Blues took their foot off the pedal after half time and allowed the Gills back into the game.
The home side however never really troubled Maik Taylor with a sequence of tame long range efforts.