Joe Rothwell's 62nd-minute strike awarded Blackburn their fifth away win of the season as Middlesbrough lose just their third game at home this campaign.
A resolute Rovers defense managed to hold on to a precious three points after Tony Mowbray's front three combined to condemn Neil Warnock's Middlesbrough.
• Story of the match
Both teams struggled to get going in the first 45 as neither side was able to get hold of any meaningful possession.
Blackburn looked as if they could be dangerous in the attacking third early on but their final ball was not good enough to create any real goal-scoring opportunities.
The biggest talking point of the half came in the 18th minute when Middlesbrough arguably should have been awarded a penalty.
On-loan Everton defender Jarrad Branthwaite went to clear a ball that was played into the Rovers box when his high boot collided with Dael Fry's head, but after a heavy appeal, the referee waved play on. A decision Middlesbrough will certainly feel hard done by.
Middlesbrough settled into the game as the half went on and they began to dominate possession in the latter stages but again, their quality in the final third of the pitch was poor.
Wingers Marcus Tavernier and Duncan Watmore were not as involved as they would have liked, as they failed to have much impact and frontman Britt Assombalonga was feeding off scraps as he struggled to get into the game.
Mowbray's side looked most threatening when their full-backs, Barry Douglas and Ryan Nyambe pushed on as they forced the Boro defense to retreat.
Although the offensive play from both sides was fairly dismal, credit has to be given to both team's defenses who stood strong whenever either side looked to break. In the closing stages of the half, Warnock's men looked the most likely.
The second half was a much more lively affair. Boro started with three shots in the first five minutes, Tavernier coming closest but his low drive was saved well by Thomas Kaminski.
Warnock's men continued to attack with much more intensity and they started forcing Blackburn into their own half, making them defend in numbers.
Boro's persistence was nearly rewarded in the 60th minute when a perfect corner found the head of Assombalonga. His original header was parried only as far as Nathan Wood who had the goal gaping but his follow-up crashed off the post.
Then, somewhat against the run of play, the Rovers front three came to life in the 62nd minute.
Harvey Elliott played a lovely one-two with the Championship's joint top scorer Adam Armstrong, before pulling an exquisite ball back to Joe Rothwell who had time to pick his spot and easily fire past Marcus Bettinelli to make it 1-0.
After a triple substitution from Blackburn in the 63rd minute, Mowbray's men managed the game excellently to see off Middlesbrough.
In the latter stages, as Boro looked to attack, Blackburn could have added to their tally as they countered in numbers but Armstrong failed to trouble Bettinelli on two occasions.
That win puts Blackburn within six points of sixth place as Middlesbrough miss out on a chance to put real pressure on the play-off places.
• Stand out player
Darragh Lenihan was superb in defense for Rovers this afternoon.
For the first hour of the game, Middlesbrough looked the most likely to score but it was only because of some resolute and determined defending from Lenihan that the score stayed 0-0.
Lenihan won nine duals, made two interceptions, four clearances and gave away no fouls.
His discipline and composure when defending was key to Blackburn holding on in the second half as Middlesbrough looked to throw more and more men forward to try and rescue something from the game.
Blackburn have a squad good enough to challenge for the play-offs
Although today's win was not the most convincing Blackburn performance of the season, the result shows that the Rovers can win in all types of ways.
With the likes of Armstrong, Rothwell and Elliott up-front, Bradley Dack, Bradley Johnson and Davenport in midfield and Douglas, Lenihan and Nyambe in defense, Blackburn have a classy squad, that has quality all over the pitch.
If they defend how they did today, then keeping clean sheets always gives a chance for the front men to win them games.
Before the goal, the front three were unusually quiet, as Mowbray planned to replace Elliott and Rothwell just before they produced the games only real moment of quality.
The fact they can produce even when they are not on red hot form proves how dangerous this Blackburn squad can be if they continue to perform.
Middlesbrough have to be better if they are to secure a place in the top six
In today's game, although Boro looked the more likely to score, they failed to create any real clear cut chances.
Tavernier and Watmore were nowhere near as involved as they would have liked and Assombalonga was very isolated up top on his own.
Aside from their threat from set-pieces, Middlesbrough struggled to create chances from open play.
Whether that was down to some excellent Blackburn defending or a lack of ideas from Boro, they need to do more in games like that if they are to consolidate their promotion push.