After waiting 15 games for a first win of the season last term, Town wasted no time getting out of the blocks with a deserved win at the bookies' favourites for promotion.
Middlesbrough led at the break - but fortunately - Scott McDonald scoring from close range after Julio Arca's header had set him up three yards out.
Town got a deserved equaliser five minutes into the second-half, Tommy Smith scoring his first goal for the Club and Blues were ahead two minutes later, Tamas Priskin heading in after a flowing move.
Substitute Jon Stead volleyed a spectacular third only four minutes after coming on to put Blues in command and on the way to that first victory of the campaign.
Town included three debutants in the starting line-up with Marton Fulop handed the 'keeper's jersey after joining the Club from Sunderland in midweek. Fellow new signing Mark Kennedy took on the left-back role while teenager Luke Hyam joined Grant Leadbitter and David Norris in a three man central midfield.
Boro have been one of the big spenders in the Championship during the summer with Scotland internationals Kris Boyd and Kevin Thomson both making their first appearance for Gordon Strachan's side. Nicky Bailey joined the list of debutants having signed for the club from Charlton while there was a welcome return to action for the first time in 15 months for Matthew Bates.
The former Town loanee has suffered a succession of knee ligament injuries and was given a great ovation on his comeback by the home fans.
Leadbitter's free-kick was headed clear inside the Boro box in the opening minutes, Carlos Edwards then doing well to ride Willo Flood's challenge and find Gareth McAuley with his cross but Justin Hoyte cleared the danger.
Boro were forced into an early change when Flood was stretchered off following his attempt to stop Edwards' cross, Arca on for the Scotsman.
Blues continued to more than hold their own and on 20 minutes Leadbitter forced a fine save from Danny Coyne. Two minutes later, the home side were ahead though, Arca heading Barry Robson's cross into McDonald's path and the Scotland international couldn't miss from two yards.
Leadbitter tested Coyne again from distance, then David Wheater had to move smartly to stop Jon Walters getting on the end of David Norris' clever pass.
Town were inches away from an equaliser on the half hour, Priskin rising highest to head Edwards' cross against the bar from 12 yards.
Leadbitter sent Coyne sprawling across his area as he continued his personal attack on the Boro goal, while at the other end Boyd sent his lob well over Fulop's bar.
Priskin picked up the first yellow card of the season for Town after catching Hoyte slightly late, Norris then fouled on the edge of the home box, Kennedy's free-kick hitting the Boro wall.
The half finished with yet another Leadbitter shot and Norris picking up a yellow card for handball, with Blues unlucky to be going in at the break a goal down.
Town should have had a penalty inside the first minute of the second-half, Norris going down inside the box but referee Bates gave a free-kick inches outside. Leadbitter fed Edwards from the set-piece and the Trinidad international fizzed a shot at Coyne that seemed to cannon back off the 'keeper's face.
Hoyte then cleared off the line before Roy Keane's side got their just rewards on 50 minutes, Smith's low shot from the edge of the box getting a deflection to beat Coyne.
Two minutes later Town were ahead, a neat move in midfield, a right wing cross and Priskin was in the right place to head home from six yards.
Kennedy picked up a third yellow card for Blues, catching Bailey, Boro a coat of paint away from grabbing an equaliser seconds later, McDonald dragging his shot agonisingly wide.
Strachan's side had a gilt edged chance to level the scores again on the hour but Arca fired over.
Boro made a second change with Hoyte making way for Estonian Tarmo Kink, another summer signing at the Riverside, while Blues were forced into a first swap with the injured Edwards limping off to be replaced by Reggie Lambe, Town's fourth League debutant.
Wheater flashed a header wide from a corner while at the other end Peters set up Lambe but the Bermuda international pulled his shot wide.
Priskin, who seemed to take a knock, made way for Stead on 73 minutes and the striker almost scored with his first touch, Coyne making the save with his feet.
Stead made no mistake four minutes later though, thumping a volley past Coyne and into the roof of the net.
Walters tested Coyne, Norris sent a curler just wide and Arca was booked as Boro's frustration grew although the home side pressed for a way back into the game, Town never buckled to take an impressive three points from the Riverside.
Jack Ainsley replaced Kennedy for added on time to take the Town League debuts count up to five but it was the score count that mattered most.
Middlesbrough: Coyne, Hoyte (Kink 61), Wheater, McManus, Bates, Robson, Flood (Arca 10), Bailey, Thomson, McDonald, Boyd. Subs not used: Steele, Lita, Miller, Williams, Grounds. Booked: Arca.
Town: Fulop, Peters, McAuley, Smith, Kennedy (Ainsley 88), Edwards (Lambe 62), Norris, Hyam, Leadbitter, Walters, Priskin (Stead 73). Subs not used: Murphy, Hourihane, Brown, Healy. Booked: Priskin, Norris, Kennedy.
Att: 21, 882