Doubts were cast about Rangersâ€™ spirit after their 4-2 home defeat by MK Dons in the FA Cup.
But Derry, 35, insists Tuesdayâ€™s stalemate against the champs shows the Hoops are united.
He said: â€śWhen you lose 4-2, you have to reply in the right manner â€” we showed that against City. We proved a point to a lot of people and showed we are all in this together.
â€śSlowly but surely we are closing the gap.
â€śThat was a huge point for us. We now have to take that into the Norwich game on Saturday. It is no good taking a point there and then dropping three. We must progress again.â€ť