The Potters goalkeeper admitted he had made an error for the Blues' opening goal at the bet365 Stadium on Saturday as the home side slipped to a narrow 2-1 loss to the league leaders.
Grant says he was frustrated to have conceded such a sloppy free-kick from Willian but did feel he had gone on to play well, making vital saves to keep out Marcos Alonso and Pedro.
Grant told the Stoke website: "Obviously for the first goal, I hold my hands up, because I feel I should have done better with it.
"I've watched it back a couple of times and my position was very good but it was just a small detail at the very end of the save where I've misjudged the bounce of the ball.
"From my perspective it's frustrating because I've not really had too many of them (mistakes) this season but fortunately I was able to make some saves in the second half which kept us in the game. Unfortunately they've just been able to come away with all three points."