The Warriors were left empty-handed by the defeat, a late try by the Blues' Lions winger Alex Cuthbert denying them any chance of even a bonus point, and their hopes of reaching the last eight of the tournament will evaporate if they lose to the Welsh side again at Scotstoun on Friday night.
"It's frustrating that we didn't win the game, but getting nothing out of it puts us in a tough position to get out of the group," admitted Townsend. "We just have to take the next game and see if we can bounce back and have some hope going into the final two matches.
"We'll see about changes. We'll look at the game, go through it with the players, see what worked and what didn't work and see which individuals might help us. We want to get it right next week."
Glasgow suffered heavily at the breakdown, where they conceded penalties and turnovers all too easily. Chris Fusaro, the starting openside flanker, was replaced shortly before half-time, but Townsend suggested that Fusaro had been carrying a knock and that the substitution was not entirely tactical.
"We have to improve our breakdown work, be more accurate and disciplined," he said. "There were seven penalties against us in the first half, to one against them, so it was very hard to build momentum. They also won penalties in good areas.
"We just have to be more accurate when we've got the ball. We can't lose the ball in tackles. They ripped it away from us a few times, which is never good to see."
Despite the loss, Townsend was heartened by some individual performances. The coach highlighted the display of Alex Dunbar, back in action after a six-week absence, and replacement lock Leone Nakarawa, who claimed a consolation try for Glasgow in the closing stages.
Townsend said: "It was great to have Alex back. He was still carrying the ball very hard at the end of the game, so his fitness was great. He gave us good go-forward ball, we just didn't capitalise on it.
"I thought Leone was fantastic when he came on. I think most of our bench did well when they came on, in fact, which has been the case for the past two weeks, but we need the starting XV playing well too."