James Tavernier and Kemar Roofe gave Rangers the half-time lead, though the Ibrox captain’s opener after five minutes came via a wicked double deflection and then Roofe’s goal also took a touch before beating Joe Lewis.
After the interval Aberdeen improved and could have scored themselves but for two glaring misses from Lewis Ferguson off the crossbar and a sliced Fraser Hornby effort.
Glass was pleased with the response but cannot take any positives from a 4-0 reverse on the south-side of Glasgow.
“I don’t feel positive on the back of a result like this,” he said. “But I’ve seen encouraging signs since I’ve been at the club.
“I do know what’s needed to change things and I’ll make the changes that’s required, when we can.
“We’ll continue building and the players now know how we work. We have had a few disappointments along the way and this is another one.”
Falling behind so early gave Rangers a platform and the hosts were on the front foot for most of the first half, but Aberdeen’s response and aggression have given the manager hope – so long as his players can replicate the pressure from the start.
Glass added: “In the first half we weren’t good enough. We showed Rangers a little bit too much respect, I think. We didn’t get close enough to them and allowed them to play.
“But as poor as we were in the first-half the two goals Rangers scored came from two deflections.
“In the second half I thought we looked like a different team altogether and just didn’t take our opportunities. They didn’t kick the ball for 15 minutes.
“The aggression of our pressure in the second half was a lot better and we created good chances. But it has to be like that from minute one.
“To come to a place like this you have to be producing that level of performance that we did in the second half. If you don’t do that then you get what’s coming.
“When you start the game like we did here then it’s an uphill task.”