Boro have racked up the air miles this week and were only denied maximum rewards after Cardiff levelled late on to deny Neil Warnock a winning return to Wales.
After scoring the decisive goal at Bristol City in midweek, George Saville popped up once again and looked to have settled matters with another huge goal.
But Sheyi Ojo rescued Cardiff to deny Boro a second maximum haul of the week.
Leaden skies and heavy rain were always going to make the conditions difficult in the Principality and it was never going to be a spectacle.
The opening period was littered with free-kicks and both sets of players found the slippery surface tough to contend with.
Openings were at a premium. Marcus Tavernier shot over the top after the ball fell nicely for him following a short corner with the first real one of the game.
In reply, Harry Wilson curled a shot over the top after some good play by Cardiff.
It was 1-0 before half time though when Saville made it number two for the week with a glancing header from a corner beyond the reach of Alex Smithies.
Cardiff did go close before the break, responding to Boro’s opener, Keiffer Moore sending a shot just wide of Marcus Bettinelli’s left hand post.
The Boro keeper was also called upon to get down well to deny Wilson and claw away a teasing cross as the hone side finished the first half on the front foot.
Smithies was the first of the two keepers to be called into action after the break when he had to be alert to claw away a Paddy McNair corner.
Bettinelli made the save of the game when he saw a Will Vaulks effort late and got a vital touch, but Boro were aggrieved play hadn’t been pulled back for a free-kick after Tavernier appeared to take a hand in the face.
Tavernier had a big influence of the game and almost doubled Boro’s advantage when he got on the end of a Saville cross, but his header was inches over the top.
Tavernier and Marc Bola also tried their luck from distance while Marvin Johnson sent a shot just wide of the mark.
Boro were looking good bets for a second, but the home side levelled in controversial circumstances with 20 minutes remaining. Saville appeared to be floored in the melee of a corner kick, but Ojo’s effort was allowed to stand.
A spirited reply was always going to come from Warnock’s men and when Tavernier drilled a ball in to the danger zone, Djed Spence came within a whisker of getting on the end of it.
At the other end, Wilson was denied by an important block from Dael Fry, and Bettinelli did well at the resultant corner.
Ojo could have had another, but dragged his effort wide on the greasy surface, and Paddy McNair fired one over from distance as the game drew to a conclusion.