Match ends, Millwall 0, Middlesbrough 2.
Second-half goals from Emmanuel Ledesma and Albert Adomah ended Millwall's seven-match unbeaten home run to give Aitor Karanka his second win as Middlesbrough boss.
Ledesma brilliantly bent the ball into the corner from 20 yards after cutting inside from the right.
Then Adomah rounded goalkeeper David Forde before rolling the ball into an empty net in the dying minutes.
Millwall's Steve Morison had a header well saved by Shay Given.
Both goals were greeted by the Middlesbrough players holding up a shirt with the name of team mate Stuart Parnaby on after he and his wife lost what would have been the couple's first baby just four weeks short of full-term.
Karanka was appointed Middlesbrough manager in November but the ex-Real Madrid assistant boss has struggled to make an impact in the north east.
Since his appointment, Middlesbrough had won once, drawn once and lost three but Saturday's win lifts them two points above fellow strugglers Millwall.
Millwall have won just two of their last 12 matches and are four points clear of the relegation zone.
In a drab first half, Liam Feeney provided Millwall with their best moment when he burst down the right, but his tame cross could only find Boro's Jozsef Varga.
On his first league start of the season, Ledesma broke the deadlock four minutes after the restart and Richard Smallwood should have made it two but he fired the goal-scorer's cutback over from 10 yards.
Adomah did seal the points though when he rounded Forde to cap a deserved victory.
Millwall manager Steve Lomas:
"There wasn't much quality on display from either side and it's disappointing to concede again from our own attack.
"We huffed and puffed but the creativity we've shown at home in recent weeks just wasn't there.
"I'm disappointed and the players are disappointed. I understand the frustration of the fans because they want us to win."
Middlesbrough manager Aitor Karanka:
"It was very, very important for us because we are losing points in the last minute.
"Not conceding late was important for the squad. It's important for our defenders and for the keeper to keep a clean sheet.
"(Ledesma) played very well. He's the kind of player who deserves to play.
"The team is starting to take shape. I've said since the first day I'm very happy with this team. I can see them improve but we just need to win the points."
- 26AbdouSubstituted forKeoghat 73'minutes
- 27McDonaldBooked at 54minsSubstituted forEasterat 62'minutes
- 26AyalaBooked at 31mins
- 23MainSubstituted forJutkiewiczat 84'minutes
- 10EmnesSubstituted forButterfieldat 74'minutes
- 19CarayolSubstituted forLedesmaat 32'minutesBooked at 50mins
- James Linington
- Shots on Target
Second Half ends, Millwall 0, Middlesbrough 2.
Corner, Millwall. Conceded by Daniel Ayala.
Delay over. They are ready to continue.
Delay in match Emmanuel Jorge Ledesma (Middlesbrough) because of an injury.
Foul by Emmanuel Jorge Ledesma (Middlesbrough).
Andrew Keogh (Millwall) wins a free kick in the defensive half.
Corner, Middlesbrough. Conceded by David Forde.
Attempt saved. Jacob Butterfield (Middlesbrough) right footed shot from outside the box is saved in the bottom right corner. Assisted by Lukas Jutkiewicz.
Goal! Millwall 0, Middlesbrough 2. Albert Adomah (Middlesbrough) right footed shot from the centre of the box to the centre of the goal. Assisted by Emmanuel Jorge Ledesma with a through ball.
Foul by Lukas Jutkiewicz (Middlesbrough).
Mark Beevers (Millwall) wins a free kick in the defensive half.
Offside, Middlesbrough. Emmanuel Jorge Ledesma tries a through ball, but Lukas Jutkiewicz is caught offside.
Attempt saved. Emmanuel Jorge Ledesma (Middlesbrough) left footed shot from the right side of the box is saved in the top centre of the goal. Assisted by Jacob Butterfield.
Offside, Middlesbrough. Dean Whitehead tries a through ball, but Albert Adomah is caught offside.
Substitution, Middlesbrough. Lukas Jutkiewicz replaces Curtis Main.
Attempt saved. Albert Adomah (Middlesbrough) right footed shot from the left side of the box is saved in the centre of the goal. Assisted by Jacob Butterfield.
Attempt missed. Liam Trotter (Millwall) left footed shot from outside the box is just a bit too high.
Attempt blocked. Curtis Main (Middlesbrough) left footed shot from outside the box is blocked.
Attempt missed. Richard Smallwood (Middlesbrough) right footed shot from outside the box misses to the right following a corner.