Neil Warnock’s side had won three successive matches against Peterborough United, Barnsley and Cardiff City but failed to make it four as they hosted the Blues.
The loss leaves them in 11th place – still only three points from the top six, however they are also the same distance away from 19th.
The defeat means eight of Middlesbrough’s last 10 fixtures have ended with a 2-0 scoreline – unfortunately not all in their favour.
The Championship club are back on the road tomorrow evening as they travel south to take on Luton Town, who currently sit on the same points as Boro.
Here are the best of today's Championship rumours...
. BURNLEY, ENGLAND - OCTOBER 02: The official Nike Flight ball is seen during the Premier League match between Burnley and Norwich City at Turf Moor on October 02, 2021 in Burnley, England. (Photo by Alex Livesey/Getty Images)
1st November 2021 - Championship rumours Photo: Alex Livesey
1. Manchester United attempted to sign Fulham starlet
Manchester United reportedly attempted to sign Fabio Carvalho before he joined Fulham when he was a 12-year-old. Chelsea and Arsenal were also 'very keen' to land the youngster. (talkSPORT) Photo: Jacques Feeney
2. Blackpool express interest in Portuguese striker
Blackpool have shown interest in Notts County striker Ruben Rodrigues, who has scored six goals so far this season. Rotherham United and Lincoln City are also keeping tabs on the 25-year-old. (Football League World) Photo: Laurence Griffiths
3. Liverpool and Chelsea swoop for Rams' coaches
Youth development phase lead and U15s coach Matthew Thorpe has joined Liverpool, while U18s coach Adam Thorley has made the move to European champions Chelsea. The pair have been involved with the likes of Lee Buchanan, Max Bird, Jason Knight and Louie Sibley over the years. (Derby Telegraph) Photo: Tony Marshall
4. Barnsley linked with highly-rated Oldham Athletic forward
Barnsley have joined a number of clubs that have been linked with Oldham Athletic's Dylan Bahamboula. The likes of Portsmouth, Millwall and MK Dons have all expressed interest in the 26-year-old. (HampshireLive) Photo: James Gill