And the overriding emotion was one of frustration as they could and should have got the result themselves.
They were caught cold by a goal from Antoine Semenyo 44 seconds into the second-half after largely controlling the first period.
Bristol thereafter did enough to see things through, but not without moments of panic as Blues ratcheted it up and put tremendous pressure on their goal in the latter stages.
Blues gave Mitchell Roberts his first start for the Under-23s and included trialist Josh McEachran, the former Chelsea and Brentford midfielder.
Tate Campbell had his first involvement of the season, paired alongside McEachran in the centre of the park.
Bristol selected a strong side, including several players with first team experience.
The hosts showed initially, when Marcus Day tried to break in on the left of the area and get a shot away, but Campbell came in with a temendous sliding challenge to block it.
Blues first attempt came from a short corner, with McEachran shifted the ball square to Ryan Burke, whose swinging shot from 25 yards was saved.
Blues began to settle and play some nice combination football, and they were also particularly dangerous when counter-attacking swiftly, Cheick Keita's pace and Adan George's ability to play on the shoulder a factor.
They also made good use of the big diagonal and from one such pass by Joe Redmond - captain of the side in Geraldo Bajrami's absence - Kane Thompson-Sommers got on the end of a Keita cross after he had taken the ball in full flow, but it was high and off target.
Then, from a ball from left to right by Roberts, Nico Gordon eluded Hakeeb Adelakun only for the Bristol player to shove him in the back with both hands.
From the resulting free-kick, McEachran tried to surprise the 'keeper Aaron Sainsbury by whipping it at goal instead of crossing, and he two-fisted an awkward shot away.
In the 33rd minute, Blues though they should have had a penalty when Keita, moving in from the right this time, flip-flapped his way into the box somewhat fortuitously and then went over under challenge, but the referee was not interested.
Bristol had their moments and Kasey Palmer showed some quality touches, but Blues got their positioning and timing right when it mattered to ensure David Stockdale, getting some minutes action, didn't have much to do in the first-period.
Bristol made a triple substitution at the break, taking off senior players Palmer, Ashley Williams and Sammie Szmodics.
And inside 44 seconds of the restart, one of the new additions, Semenyo, fired Bristol into the lead out of nothing.
A short, forward ball by Day found Semenyo on the right of the area, he shifted the ball smartly to create space and fired it out of his feet and emphatically past Stockdale.
Keita had to be replaced by Miguel Fernandez in the 52nd minute after taking a blow to the ankle, forcing a reshuffle: Thompson-Sommers came over to left side midfield as a result to accommodate the Spaniard.
George, fresh from his hat-trick for the Under-18s last week, tried to lift the momentum when he raced onto a good ball down the right channel from Gordon; he held off his centre-half before firing a low shot that had Sainsbury diving to his near post to save.
Blues, though, had rather lost the thread. They were not as slick or vibrant as in the first-half.
It meant a change, with Rhys Hilton and Jack Concannon coming on for Josh Andrews and McEachran in the 68th minute.
Blues moved to a diamond shape and almost found a way back when Concannon helped the ball down the side to Hilton, who cut back inside a defender in the area and teed-up Fernandez, only for his considered sidefooter, towards the bottom corner, hit Aden Baldwin in the way.
All of a sudden Bristol were wobbling as Blues gave them something different to think about. They upped the tempo and moved their opponents around a lot more.
Hilton, who recently signed his first pro contract, injected some speed and directness into proceedings at the top, alongside George, with Fernandez in behind.
But it just wouldn't go for Blues as Bristol held out. In the last minute, from a ball played back in from a corner, Redmond nodded down and Roberts wasn't able to get sufficient control on his swiping shot, sending it over the bar, and that was that.
In truth, Blues didn't quite work the 'keeper as well as they might in their sporadic periods or urgency.
Blues (4-4-2): Stockdale, Gordon, Burke, Campbell, Redmond, Mitchell Roberts, McEachran (Concannon 68), Thompson-Sommers, Andrews (Hilton 68), George, Keita (Fernandez 52). Subs not used: Ramos, Sun.