In a fiercely-fought contest at the Riverside Stadium, that saw Neil Warnock's side dominate possession and take ten shots to the visitors' two, Paddy McNair's 82nd minute goal secured a draw for his side and ended the Bluebirds' relentless six-game winning streak.
Speaking after the game, Boro's boss was quizzed on the fitness of his January signings, and he claimed: "He (Nathaniel Mendez-Laing) will get sharper. He has been out a long time really. That’s the same with (Neeskens) Kebano really, he hasn’t had much football.
"Yannick (Bolasie) hasn’t either, and if you had seen him on the training ground yesterday…they told me he wasn’t fit as well.
“I think I am in the wrong game. They say he has to do longer sprints, longer runs. Hopefully he will be available at some stage before next weekend I hope.”
Middlesbrough are back in action tomorrow evening, when they travel to take on Coventry City at St. Andrew's.
Here are today's biggest transfer stories and the latest team news involving Middlesbrough and the rest of the Championship, ahead of the midweek action:
5. Keogh issues Huddersfield Town rallying cry
Following his side's seventh defeat in ten matches, Huddersfield Town defender Richard Keogh has urged his side to "stick together" and improve in a "massive" game against fellow strugglers Birmingham City tomorrow night. (Club website)
Photo: George Wood
6. Kane reveals Blades approach
QPR midfielder Todd Kane has revealed he nearly joined Sheffield United two seasons ago, during his time at Chelsea, but saw the move fall through due to the Blues focusing their attentions on capturing Gonzalo Higuain on loan from Juventus. (The 72)
Photo: Warren Little
7. Rovers set for pitch overhaul
Blackburn Rovers are preparing to splash the cash on a new £2m overhaul of their playing surface, with a grass/artificial surface combination and improved under-soil heating set to revitalise their stadium facilities. (Lancashire Telegraph)
Photo: Jan Kruger
8. QPR take Gunners youngster on trial
QPR have brought Arsenal teenager Luke Plange in on a trial, as they weigh up a potential move for the 18-year-old striker this summer. He's likely to be released by the Gunners at the end of the current campaign. (West London Sport)
Photo: Julian Finney