Boro were left frustrated as an early Leeds United goal proved the difference at the Riverside.
Daniel James fired the visitors in front after less than two minutes and Boro spent the remainder of the game searching for an equaliser.
Michael Carrick’s side probed until the end but a goal eluded them, despite a number of fine opportunities being carved out.
Possession
47%Shots
5Shots On Target
3Corners
4Fouls
101
0
Cards
1
0
There was one change to the Boro team which started the 2-0 win over Blackburn Rovers last Friday, with Rav van den Berg introduced for the injured Neto Borges.
The visitors struck the first blow in less than two minutes, with James forcing the ball home from close range.
That was the start of an entertaining opening 45 minutes as the teams traded blows.
James had two further sights of goal in the early stages, forcing Mark Travers into a parry before curling another over.
Boro then had a bright spell of their own, with Kelechi Iheanacho and Finn Azaz off-target with efforts and Tommy Conway denied by the offside flag after firing in from close range.
Leeds also had celebrations cut short after Ao Tanaka’s finish was ruled offside and Boro responded with a quick break which led to Iheanacho striking over.
The visitors carried their one-goal advantage into half-time but there were plenty of positives for Boro to draw on.
Middlesbrough: Travers, Dijksteel, Howson, van den Berg, Iling-Junior, Burgzorg (Forss 80'), Morris, Hackney, Azaz, Iheanacho (Whittaker 66'), Conway
Subs: Barlaser, Fry, McGree, Whittaker, Forss, Glover, Giles, Woolston, McCabe
Leeds: Darlow, Bogle, Rodon, Ampadu, Firpo (Byram 68'), Tanaka, Gruev, James (Schmidt 73'), Aaronson, Solomon (Gnonto 68'), Piroe (Bamford 73')
Subs: Meslier, Bamford, Ramazani, Joseph, Guilavogui, Byram, Gnonto, Schmidt, Wöber
Leeds had the first strike on goal in the second half, with Travers doing well to close the angle and save from Joel Piroe.
There was another sigh of relief for Boro when James’ ball across the face of goal was not converted.
Iling-Junior sparked fresh life into the home side with a driving run and cross which was struck over by Azaz.
Delano Burgzorg was the next to go close with a drilled effort which went wide, before Hayden Hackney saw a volley held by Karl Darlow in the Leeds goal.
Burgzorg was then denied by Darlow after being found by Hackney, who later curled wide from distance as Boro continued to search for an equaliser.
We were frustrated again when Hackney’s strike was blocked and the loose ball bounced to Burgzorg, whose effort fizzed wide.
A vital touch by Jayden Bogle denied Conway a tap-in as the game entered its final 10 minutes, with substitute Morgan Whittaker later firing over from outside the area.
A goal would not prove forthcoming, though, as Leeds took all three points.