Ends Boro’s run
strike after he met Yannick Bolasie’s low delivery first time.
That was a sign of things to come. Villa looked dangerous every time they broke and the home side could not get hold of the play and Abraham had a strong penalty shout dismissed when he was tripped by George Friend.
It was no surprise when Chester forced in the opener soon after.
Jack Grealish’s corner was misjudged by Randolph. Defenders Danny Batth and Dael Fry both lost Chester, who was able to force the ball over the line from six yards.
As half-time approached Middlesbrough went close to levelling. Mo Besic had an effort saved and Stewart Downing went close twice, once when he was unmarked at the back post and secondly his volley was blocked by team-mate Hugill.
Middlesbrough pressed after the restart but struggled to test goalkeeper Orjan Nyland. All they could muster before the hour was a Downing effort that flew high into the North Stand.
And soon after Middlesbrough manager Tony Pulis tinkered with his forward line, the Villans made it two.
Bolasie, wanted by the Teessiders in the summer, was left with space to drill a low cross into the area for Abraham to slide in and apply the finish.
And then Whelan, moments after coming on, wrapped it up when Randolph helped his long distance drive in off the left hand post.