Burnley's unbeaten home start was brought to a tame end as away-day specialists Boro gained a measure of Turf Moor revenge.
The Teessiders' last defeat came at Burnley back in April, since when they have won seven straight games on the road and now a club record-equalling five successive times away from home in the Championship.
By contrast, the Clarets have not won at home in the League since that 3-1 success and goals early in each half from Nicky Bailey and Joe Bennett made sure that record would not be improved.
Burnley had no reply on a collective off-day as they got nowhere near the heights of their win at Derby County ahead of the international break.
Boss Eddie Howe picked the same team but there the similarities ended as the Clarets were second best to a Boro side which extended its impeccable away form to stay among the early season pace-setters.
The visitors, with only three wins in their previous 25 visits to Turf Moor, may have feared the worst when they were forced into a defensive re-shuffle inside the opening minutes when Stephen McManus limped off.
David Edgar hooks a shot against the bar
Former Clarets' loanee Rhys Williams dropped into the back four but the visitors re-shaped back line was never seriously tested as Burnley struggled to make an impact throughout the opening half.
And Boro, riding the crest of a wave away from home, quickly went ahead with pretty much their first attack with ten minutes gone.
Top scorer Marvin Emnes led the break which ended with Barry Robson crossing deep for Justin Hoyte to hang the ball up in Burnley's box.
Jay Rodriguez tries to get Burnley moving
Brian Easton rose to head clear but Bailey's connection with a bouncing volley was enough to send the ball through a group of players and beyond Brian Jensen's despairing dive.
The goal and a succession of injury stoppage did little to help Burnley find any rhythm and it was Boro who continued to look the more threatening, Emnes letting fly with a shot that Ben Mee blocked with his body.
There was precious little coming back from Burnley as they struggled to pass their way through the ranks of black shirts, although David Edgar almost levelled after 27 minutes when a deflected shot from Jay Rodriguez gave the Clarets a rare corner.
Chris McCann challenges Barry Robson
Ross Wallace's delivery was headed down by Mee and Edgar, showing no ill effects from his globe-trotting World Cup exploits with Canada, hooked his foot around the ball to steer a left-foot volley against the top of the crossbar in the nearest the Clarets came to scoring in a poor first 45 minutes.
Howe stuck with the same personnel but tweaked his formation at the break to try and engineer a fightback as the Clarets switched to a 3-5-2 line-up in a bid to stifle the Boro midfield.
But just four minutes into the second half they were left with even more to do as the Teessiders increased their lead.
Bennett's forward burst had Burnley badly stretched and when the young full-back continued his run into the box he was in the right place to bundle home his first ever League goal after Jensen had saved Scott McDonald's angled drive.
The goal was the signal for Howe to send on Junior Stanislas for his Burnley debut and the deadline-day signing made an immediate impact as the Clarets almost got themselves back in the game.
Edgar threatens again from a corner
Stanislas worked the ball out wide to Kieran Trippier and when Trippier combined well with Chris McCann, Clarets' skipper McCann forced Carl Ikeme to make his first save of the afternoon with a fierce drive which the on-loan keeper turned round the post at full stretch.
Sadly for Burnley that was not a sign of things to come, though, as they were unable to build any sustained pressure.
When Charlie Austin got a rare sight of goal, the Clarets' leading scorer failed to capitalise, shooting too early after Jay Rodriguez had got away with a foul on Matthew Bates to leave his strike partner in the clear.
And if there was to be a third goal it should have gone Boro's way as Emnes missed a golden opportunity to make the win even more emphatic.
Charlie Austin is thwarted from a rare attack
Hoyte's pass to Emnes as the visitors broke following a corner left the Dutchman with just Jensen to beat but his poor touch allowed the Clarets' keeper to come out and save and spare his side further punishment.
Burnley: Jensen, Trippier, Easton, Mee, Edgar, McCann, Marney (Bartley 70), Wallace, Rodriguez, Austin (Hines 70), Treacy (Stanislas 52). Subs: Amougou, Grant.
Booked: Treacy 20, Wallace 36, Rodriguez 89.
Middlesbrough: Ikeme, McMahon, Bates, Hoyte, McManus (Haround 4), Williams, Bailey, Bennett, Robson (Arca 81), McDonald, Emnes (Zemmama 86). Subs: Kink, Martin.
Booked: Bennett 13, Robson 23
Referee: Mark Haywood.