Blues kept going right to the end and Bailey sent the home support into raptures with his 89th minute winner and. first senior goal for the Club.BCFC
Boro looked to have snatched an undeserved point when Dani Ayala bundled the ball home in the 87th minute to level Fran Villalba’s first-half goal for the hosts.
But Blues kept going right to the end and Bailey sent the home support into raptures with his 89th minute winner.
In what was undoubtedly Blues’ best performance of the season they were superb from start to finish against the Teessiders and had it not been for the woodwork and an outstanding display from Randolph in the Boro goal they could have been out of sight.
Pep Clotet made two changes to side that had narrowly lost at Wigan earlier in the week with Jude Bellingham replacing Gary Gardner in the centre of midfield and Marc Roberts returning in the centre of defence instead of Jake Clarke-Salter.
Blues made a really positive start as they zipped the ball around in the opening exchanges.
And they were almost rewarded inside three minutes when Maxime Colin found room down the right before pulling the ball back in front of the Boro goal. It found Villalba some 10 yards out, but his powerful goalbound shot was brilliantly saved by former Blues ‘keeper Randolph who tipped it behind for a corner.
Blues began to pile on the pressure and started to largely pin Boro back in their own half.
The lively Bellingham set up the next chance for the hosts as he swung in a neat cross from the right, which Alvaro Gimenez headed narrowly wide of the upright.
Blues were a fraction of an inch away from taking the lead on 12 minutes. Villalba floated a cross into the box which was headed down by Roberts. It struck Boro defender Dael Fry and was heading into his own net before Randolph sprang into action once again and tipped the ball onto the bar.
Backed a vociferous crowd Blues were continuing to dominate and Colin was next to try his luck with a flashing shot from the right that flew several yards off target.
Randolph was the saviour again for Boro on 22 as he just about tipped the ball over the bar after it had deflected off ex-Blues defender Ryan Shotton from Colin’s cross.
Middlesbrough were then awarded a contentious free-kick just outside the Blues penalty area. Marcus Tavernier struck it really well, but Lee Camp was equal to it and turned it behind for a corner.
Blues finally got the goal that their play deserved just after the half-hour mark and what a goal it was.
Villalba flighted a brilliant ball out to the right flank to Colin. The full-back sent in a low first time cross which was met by Villalba who swept home a low shot past the diving Randolph.
The busy Boro stopper was called into action again just ahead of the break when Roberts launched a trademark throw in deep into the Boro box where it was met by Kristian Pedersen who headed it towards goal, but Randolph was able to tip it over.
A minute later the Republic of Ireland international almost suffered a major embarrassment as he fumbled Harlee Dean’s header on his own line, but luckily, he managed to prevent it going in at the the second time of asking.
Right on the stroke of half-time Blues were denied by the bar for a second time as Pedersen’s header struck the woodwork and dropped down before being cleared away.
Half-time: Blues 1 Boro 0
Blues began the second period of the game that had ended the first – on the front foot.
And they caused problems almost immediately as Lukas Jutkiewicz beat his marker deep inside the Boro box, but his dangerous cross was scrambled away.
Alvaro Gimenez then tried his luck with a curling effort from just outside the box, but he just failed to get his foot around it enough and it went several yards wide.
His strike partner Jutkiewicz then saw his attempt deflected behind for a corner.
With just 56 on the clock Boro manager Jonathan Woodgate was forced into a double tactical solution as he sent on Lewis Wing and Ashley Fletcher for Adam Clayton and Marcus Browne.
With just over an hour played Boro began to enjoy their best spell, but despite getting the ball into the Blues box several times, the hosts dealt with it comfortably and cleared it away from the danger zone.
Camp had to be alert when Paddy McNair sent in a teasing cross from the right, but the Blues keeper tipped it away at full stretch from inside his own six-yard box.
Blues made their first change of the evening on 74 when Gary Gardner was sent on for Bellingham and then two minutes later Jacques Maghoma replaced Fran Villalba.
Blues were oh so close to doubling their advantage on 81 minutes as Gardner struck the post with a curling shot, after Maghoma’s initial attempt on goal had been blocked.
Then completely against the run of play Middlesbrough somehow found an 87th minute equaliser. Blues failed to clear their lines and Britt Assombalonga was the provider as he lifted the ball over Camp and Ayala forced it home from a yard out to the despair of the home support.
But despair turned to jubilation just two minutes later as Bailey stepped up with the winner. Crowley fired in a cross from the right and there was Bailey to head home into the back of the net. 2-1 Blues!
Blues: Camp, Pedersen, Roberts, Dean, Colin, Bellingham (Gardner, 74) Sunjic, Crowley, Villalba (Maghoma, 76), Gimenez, Jutkiewicz (Bailey,83).
Subs (not used): Stockdale, Harding, Clarke-Salter, Davis.
Bookings: Sunjic (86), Baily (90).
Goals: Villalba (33), Bailey (89).
Boro: Randolph, Dijksteel (Gestede, 82), Ayala, Fry, Shotton, Clayton (Wing,56), McNair, Howson, Tavernier, Browne (Fletcher, 56), Assombalonga.
Subs (not used): Pears, Bola, Saville, Johnson.
Bookings: Dijksteel (64), Shotton (73).
Goals: Ayala (87).
Referee: Jeremy Simpson.
Attendance: 19, 703 (789 Boro fans).