An own goal from visiting defender Jordan Storey and a second-half header from Marcus Tavernier gave Boro all three points, while there was also a controversial red card for Preston’s Alan Browne.
The midfielder was dismissed in the 36th minute following a tussle with Sam Morsy, a decision which North End boss Alex Neil described as ‘very poor’ and altered the course of the game.
Boro were 1-0 up at the time but coming under pressure, yet they looked comfortable playing against 10 men in the second half.
The result moved the Teessiders up a place to eighth in the Championship table and five points off the play-off places.
That gap could widen again, though, with promotion rivals Reading and Barnsley set to play on Wednesday.
Here’s how the hosts fared at the Riverside:
1. Marcus Bettinelli - 6
Spilled an early cross from Paul Gallagher. Didn’t have much to do in the second half. 6 Photo: Alex Burstow
2. Darnell Fisher - 7
Tried to get forward from right-back in the first half but was forced to do more defending before Preston were reduced to 10 men. 7 Photo: George Wood
3. Grant Hall - 8
Kept Preston striker Ched Evans under wraps in the first half and was comfortable stepping out from the back. Has consistently impressed since returning from injury. 8 Photo: Stu Forster
4. Dael Fry - 8
Another solid display alongside Hall at the back. Helped Bettinelli out of trouble in the first half. 8 Photo: Getty Images