Boro had failed to pick up a point in the new year before this clash and had seen their play-off place come under increasing threat from a number of chasing clubs, which Leeds considered themselves to be one of.
But with United struggling with form issues of their own, they were unable to present a consistent threat and suffered their first defeat at the Riverside since it opened in 1995.
Come the end their fans were chanting `Warnock, time to go' at their under-fire manager Neil Warnock, while in the opposition dugout Tony Mowbray was left celebrating, even in spite of Main's dismissal four minutes after his 81st-minute goal.
The striker's back-post header from Ishmail Miller's cross was reward for Middlesbrough's second-half improvement, although they had to weather a slight first-half storm as an unchanged Leeds impressed early on.
- Sports & Recreation