Rovers' Under-18s FA Youth Cup campaign ended at the first hurdle as they slipped to a 1-0 loss at Cardiff City.
A close contest at the Cardiff City Stadium was settled by a second half strike from winger Yora Enzam on a disappointing night for David Lowe's youngsters.
Rovers started brightly but it was the home side who created the better chances, David Raya called upon to make important saves.
Both sides rattled the woodwork in the second half but it was the home side who grabbed the all-important goal, Enzam firing home after near approach play.
Rovers threw everything forward in the closing stages but when Ian Vicars' deep cross bounced off the top of the crossbar you knew it wasn't to be their night.
David Lowe named the same starting eleven that defeated Newcastle United 4-1 last time out.
It was an eleven with plenty of experience as David Raya, Ian Vicars, Bradley Bauress, Jack Doyle, Jordan Preston, Brice Wassi and Dean Rittenberg have all played for the Under-21s this season.
That experience showed in the early exchanges as Rovers dominated territorially without threatening meaningfully as the home side were content to get men behind the ball.
On the quarter hour a cross from Dean Rittenberg saw Yeray Torres go for the ball but the Spaniard's header was off target.
Then a cheeky effort from Brice Wassi curled just beyond the far post.
Despite Rovers seeing more of the ball, it was the home side who had the better of the chances.
A Thomas Burridge free-kick from the left found central defender Thomas James but his free header was well claimed by David Raya.
Then a bouncing ball in the Rovers are saw two Cardiff men closing in but Raya was alert to claim the ball.
The first half ended with two further chances for the hosts, a neat move down the right saw Tyler Roche feed Dylan Rees, but his cross was headed wide by Yora Enzam.
Then two minutes before the break the Bluebirds spurned another opportunity, a ball into the area was inexplicably headed back into the danger-zone by Jordan Preston but Raya saved well to deny Eli Phipps.
Rovers were sloppy starters at the beginning of the second half as the hosts spurned a trio of fine opportunities.
Early after the restart a Thomas Burridge free-kick found Tyler Roche but his header was cleared by Jordan Preston.
Moments later and Burridge again was provider as he drove goalwards to find Ben Watkins but Raya easily saved his left-footed effort.
On 55 Cardiff came once more requiring a big save from 'keeper David Raya, Bluebirds wide-man Tyler Roche getting the better for Jack Doyle to race through on goal, but the Spaniard stood strong to make the save.
Rovers hit back with three chances in the space of as many minutes, all falling to Callum Harris.
The first saw Harris almost take advantage of a defensive mix-up as the ball rolled beyond defender and goalkeeper, but somehow it struck the foot of the post. Then Dean Rittenberg teed up Harris but his shot from the right was well saved.
A third chance for Harris soon followed but from a good position he fired high over the bar.
Rovers pressed further, Dean Rittenberg denied twice, first a good save from Massaro before his rebound was well blocked.
It was end-to-end, and as Cardiff raced away they thought they had opened the scoring only for Yora Enzam to see his shot crash off the underside of the crossbar and away.
However a minute later the home side, and Enzam, would be celebrating as they scored the only goal of the game. A ball in from the right finding the winger and he fired beyond Raya.
Just moments earlier he had signalled to come off with cramp, yet he played on and would have the decisive impact.
That goal finally shocked Rovers into action and they pressed for an equaliser in the closing stages. Dean Rittenberg's effort cleared off the line in a goalmouth scramble.
Callum Harris saw a near-post shot well kept out by Massaro then with the last chance of the game the woodwork was rattled, Ian Vicars deep cross was missed by the Cardiff keeper, but luck deserted them as the ball bounced off the crossbar.
It was a match where both sides showed plenty of endeavour, this tight encounter settled by a solitary second half strike.
CARDIFF: Massaro, Rees, Tutonda, Burridge, C. Watkins, James, Roche (sub Pearson 74 mins), B. Watkins, Phipps (sub Noor 63 mins), Southam (c), Enzam (sub Patten 88 mins).
Subs not used: Loveys (GK), Veale.
Goals: Enzam 79 mins.
ROVERS: Raya, Vicars (c), Doyle (sub Langford 87 mins), Bauress, Butterwick, Pierce (sub Cham 84 mins), Rittenberg, Wassi, Preston, Torres (sub Joel 60 mins).
Subs not used: Williams (c), Lavelle.