Rovers Under-23s slipped to their first defeat of the season, going down 3-1 to Middlesbrough in a top-of-the-table clash at Ewood Park.
Both sides went into the game with 100% records in the Premier League 2, with three wins out of three, but it was Boro who came from behind to secure the spoils.
Fresh from bagging a brace in the Lancashire FA Senior Cup success over Wigan Athletic seven days ago, Joe Rankin-Costello opened the scoring for Rovers on 16 minutes, converting Lewis Travis' cross.
The hosts dominated the first half - and much of the match - but Middlesbrough equalised just past the half-hour mark when Luke Armstrong smashed a shot into the top corner against the run of play.
The visitors extended their lead at the start of the second half, courtesy of George Miller's stunning long-range strike, before Lewis Wing made the points safe with a stoppage-time third.
It was harsh on Rovers, who created countless chances in the second half to take something from the game, before seeing Joe Grayson sent off through frustration right at the death.
The game started at a blistering pace, with Rovers creating three good chances in the opening four minutes.
With just 45 seconds on the clock, Rovers should have been awarded a penalty. Stefan Mols latched onto a diagonal ball from Grayson and burst into the box, where he was clearly felled by the covering defender, but only a corner was given.
From the resulting play, Lewis Hardcastle advanceed along the byline before crossing for Willem Tomlinson, who saw his first-time shot blocked close to the Boro goal-line.
Moments later, Rovers threatened again. A corner was played short to Travis, who delivered a dangerous ball into the box and Joe Nuttall glanced a header inches wide.
The goal Rovers' early dominance deserved arrived just past the quarter-hour mark - and what a well-worked goal it was.
Charley Doyle found Travis in space down the right and his pin-point centre was sweetly swept home by Rankin-Costello for his fifth of the season.
The hosts created two further chances in quick succession at the midway point in the half, as Grayson's free-kick had to be palmed around the post, before Nuttall engineered space for a shot, but fired straight at Aynsley Pears.
Rovers went close again just before the half-hour mark, as Mols again burst into the box, but he drilled a low shot just past the outstretched boot of Rankin-Costello and the far post.
Then, completely against the run of play, the visitors equalised on 33 minutes. Miller caused concern in the Rovers defence, who were unable to clear their lines and Armstrong smashed the loose ball right into the top corner.
Ten minutes later and Rovers ended the half with another good chance. Travis beat his full-back down the right, before laying the ball square to Nuttall, whose shot from the edge of the area deflected kindly into Pears' arms.
Just like they did in the first half, Rovers started the second strongly and had a great chance to regain the lead less than three minutes after the restart when Rankin-Costello played in Nuttall, but he dragged his shot wide of the far post.
However, out of nothing, it was the visitors who went in front soon after. A long ball forward was flicked on by Miller, who got to the bouncing ball himself, before firing a stunning 35-yard volley over Andy Fisher and into the back of the net.
Rovers responded well and spent virtually the remainder of the match camped in the Boro half.
A last-ditch challenge prevented Jack Doyle from a certain tap-in, after good work from Nuttall, before Hardcastle drilled a low shot from the edge of the area just the wrong side of the post.
Rankin-Costello and Nuttall then both headed efforts over the bar.
Rovers brought on Lewis Mansell in place of Charley Doyle as they looked for that elusive equaliser and the substitute almost provided it, but his shot from the edge of the area deflected just over the bar.
As the game entered the closing stages, Matty Platt twice headed two Grayson corners over the bar from close range, before Jack Doyle came to Rovers' rescue, twice throwing his body on the line as Boro were content to play on the break.
Arguably the best chance of the half came on the 90-minute mark when Nuttall crossed from the right, but the unmarked Mols headed wide when well placed.
The misses proved costly, as Middlesbrough wrapped up the points in the third minute of added time when a corner was played short to Wing, who escaped the clutches of two Rovers players along the byline, before cutting inside a third onto his left foot and stroking the ball past Fisher at his near post.
There was still time for Grayson to see red late on, as Rovers' unbeaten start to the season came to an end.
The development squad will now look to bounce back from the setback when they travel to Norwich on Sunday.
ROVERS: Fisher, Travis, C. Doyle (Mansell 76), Platt, Grayson, J. Doyle, Tomlinson, Hardcastle (Wright 90), Mols, Rankin-Costello, Nuttall.
Subs not used: Albinson, Paton, Thomson.
Goal: Rankin-Costello (16)
Booked: Grayson, Nuttall
Sent off: Grayson
MIDDLESBROUGH: Pears, Cook (Storey 61), Dale, Wing, Brewitt, McGinley, Soisalo (Malley 76), Liddle, Miller, Armstrong, Tavernier.
Subs not used: Hemming, Curry, Wilson.
Goals: Armstrong (33), Miller (51), Wing (90+3)