The Potters were on course to claim a share of the spoils after Jonathan Walters' penalty had cancelled out Willian's early free-kick, but Chelsea captain Gary Cahill broke City hearts late on with a close range strike.
It was a tough loss to take for Mark Hughes' troops who had battled valiantly throughout the contest in North Staffordshire, and despite being frustrated at the loss, Grant says the team can be pleased with their efforts against the runaway Premier League leaders.
"We are disappointed because this was a game we'd highlighted as one we thought we could get something out of," the 34-year-old expressed.
"I think the attitude and level of performance was really good so to come away with nothing off the back of nothing more than a couple of mistakes for the goals is really disappointing.
"That's probably the most disappointing thing about the day because with the level of work-rate, endeavour and organisation we were just undone on a couple of little details.
"Obviously for the first goal I hold my hands up because I feel I should have done better with it.
"I've just 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 just misjudged the bounce of the ball.
"From my perspective it's frustrating because I've not really had too many of them this season but fortunately I was able to make some saves in the second half which kept us in the game.
"However, as I've said, unfortunately they've just been able to come away with all three points."