|Main 75||Venue: Riverside Stadium
|Friend (og) 25, Woolford 39|
MILLWALL ground out a priceless away victory to halt their five-match losing run and get their season back on track.
Former Den loanee George Friend headed in an own goal and Martyn Woolford scored his first goal for the club to put the Lions in control.
Curtis Main gave Middlesbrough a fighting chance when he tapped home 15 minutes from time before Scott McDonald had a stoppage-time equaliser disallowed, but the visitors held on.
Manager Kenny Jackett made five changes to his side following their 5-1 thrashing by Peterborough in midweek, with mainstays Liam Trotter, Andy Keogh and Adam Smith all dropped to the bench.
Rob Hulse (stomach injury) and Shane Lowry (suspended) also dropped out of the starting line-up, meaning Josh Wright, John Marquis, Martyn Woolford, Danny Shittu and Alan Dunne all started.
Captain Shittu was passed fit after a double-dose of injury and illness and immediately returned to the heart of the defence, while striker Nathan Tyson was back on the bench after an ankle problem.
Both sides came into the match on bad runs of form and so the nervy start made by both was no surprise, although Marquis had a half-chance from Benik Afobe's knock-down, but missed his kick.
In the 16th minute, Grant Leadbitter curled a free-kick a yard over the crossbar from the edge of the area after Karleigh Osborne had been booked for tripping Main.
But Millwall drew first blood when Henry's deep free-kick was headed into his own goal by Friend at the back post under pressure from Osborne and Marquis, who initially claimed the goal.
Middlesbrough's response to going behind was limited to Leadbitter's piledriver from the edge of the area which flashed wide of the far post in the 34th minute.
There was a moment of panic for the visitors when David Forde failed to claim Friend's cross into the area, clattering Marvin Emnes and Andre Bikey instead, but the ball was cleared by Beevers.
And the Lions doubled their advantage moments later when Woolford tucked home the rebound after Afobe's shot had been parried into the winger's path by goalkeeper Jason Steele.
Friend blasted over from distance just before half-time but Jackett's side came in at the interval with a healthy lead to defend in the second 45 minutes.
Boro made a double substitution at the break, bringing on Ishmael Miller and Mustapha Carayol, in an attempt to inject some urgency into their attacking play.
Bikey headed over from Leadbitter's corner before sub Miller curled high wide after Friend's driving run and pass in the 57th minute as the home fans grew increasingly restless.
Forde made a crucial save to deny Carayol on the hour mark, getting down quickly to his near post to prevent the winger's close-range shot from squeezing in.
Millwall nearly extended their lead on the counter-attack when Afobe burst past Friend and drove low towards the far corner, but the ball trickled agonisingly wide with Steele beaten.
Marquis should have made it 3-0 when Henry's cross dropped to him in acres of space inside the area, but he rushed his shot and did not strike the ball cleanly.
And that miss proved costly when Middlesbrough went up the other end of the pitch and pulled a goal back courtesy of Main's tap-in from Friend's cross.
Main should have equalised for Tony Mowbray's side in the 86th minute but he somehow sliced a half-volley wide with Forde rooted to the spot.
Middlesbrough thought they had snatched a point when McDonald turned in Carayol's cross at the near post, but the flag was raised for offside.
Middlesbrough: Steele, Friend, Bikey, McManus, Dyer (Carayol, 46mins), McEachran, Leadbitter, Bailey, Main, Emnes (McDonald), Williams (Miller). Subs not used: Ripley, Ledesma, Hines, Smallwood.
Millwall: Forde, Dunne, Beevers, Abdou, Shittu, Osborne, Woolford, Wright, Marquis, Afobe, Henry. Subs not used: M.Taylor, A.Smith, Trotter, Keogh, Malone, Tyson, N'Guessan.