Alan Smith came off the bench to rescue a point in a below-strength Manchester United performance against Boro.
The injury-hit Teessiders produced a stirring defensive display and took the lead when Stewart Downing sidefooted in after fine work by James Morrison.
Ruud van Nistelrooy headed against the woodwork and saw a close-range effort deflected over by Stuart Parnaby.
Smith headed in a Cristiano Ronaldo cross with nine minutes left and Gary Neville could even have won it late on.
Middlesbrough went into the game with a fine record against United in recent seasons - having won on two of their three previous visits.
But their task looked a difficult one without the likes of Mark Viduka, Jimmy Floyd Hasselbaink and Ugo Ehiogu.
Sir Alex Ferguson decided to unleash the three Rs on Middlesbrough, with Wayne Rooney and Van Nistelrooy up front and Ronaldo making a return.
It took only seven minutes for Rooney and Ronaldo to combine for the first time, with the Portuguese winger then releasing John O'Shea with a clever backheel.
The Irishman drilled in a shot that Mark Schwarzer, who has been linked with a move to Old Trafford, did well to hold on to.
United had the first real chance when Mikael Silvestre headed down a Ryan Giggs corner and Van Nistelrooy appeared to have the simple task of tapping in but Parnaby somehow managed to deflect the ball over the bar.
Middlesbrough struggled to get going in the early stages and their only meaningful attacking contribution to the opening 25 minutes was an ambitious Downing shot that was well over the bar.
But they gradually gained a foothold in the game, with their uncompromising defence and careful possession frustrating the home side and their fans.
Rooney and Ronaldo desperately tried to make it happen for a stuttering United but it was two of Middlesbrough's less-heralded youngsters who made the more telling contribution.
Downing started the move that led to their goal by picking out Morrison with a fine cross-field ball.
Downing (left) put Middlesbrough ahead
The 18-year-old skipped around the challenge of Gabriel Heinze before firing in a cross that beat a host of United defenders and found Downing unmarked at the back post to sidefoot home.
United tried to answer with a Roy Keane lay-off finding Ronaldo but his well-struck shot was blocked by Gareth Southgate, who was again outstanding at the heart of the Boro defence.
Heinze then headed just wide from a corner as the home side looked to step up a gear.
But with United throwing numbers forward Middlesbrough broke and Gaizka Mendieta blew a glorious chance for a second goal when he blazed over from 12 yards out, with time and space to spare.
United went to all-out attack, introducing Smith as an extra striker in place of O'Shea.
They looked to have equalised when Van Nistelrooy stooped to meet a Neville cross with his head but, while his effort beat Schwarzer, it clipped the top of the crossbar.
Ronaldo fired in a centre that just evaded Neville in front of goal and it was beginning to look like one of those days for United.
But when Ronaldo again sent in a ball from the right side, Smith arrived late to rise above a couple of defenders to power a header past Schwarzer.
Neville should have won the game but he fired over from close range.
However, it would have been cruel luck for Steve McClaren's side had United taken all three points.
Man Utd: Carroll, Gary Neville, Ferdinand, Silvestre, Heinze,
Ronaldo, O'Shea (Smith 69), Keane, Giggs, Rooney,
Subs Not Used: Ricardo, Kleberson, Djemba-Djemba, Fortune.
Goals: Smith 81.
Middlesbrough: Schwarzer, McMahon, Riggott, Southgate,
Parnaby (Cooper 35), Morrison (Doriva 79), Mendieta, Boateng,
Downing (Graham 87), Zenden, Nemeth.
Subs Not Used: Nash, Taylor.
Booked: Mendieta, Boateng, Nemeth.
Goals: Downing 33.
Ref: R Styles (Hampshire).