Steve Agnew celebrated his first win as manager of Middlesbrough to keep his hopes alive of keeping Boro in the Premier League.
Marten De Roon showed his composure to score the only goal of the Tess-wear derby, finishing well in the eighth minute from Adam Clayton's long ball.
It was Agnew's first win in seven matches in charge and ended a 16-match run without a victory for Boro, who are now six points from safety.
"I'm pleased," said the former Sunderland midfield. "Not so much for me, but for the players, staff and supporters.
"It was a reward for the all the work that has gone in."
Exciting it was not, but Agnew was not complaining.
Stewart Downing was foiled by Jordan Pickford who saved superbly with his feet while after the break, Wahbi Khazri had a free-kick well saved by Brad Guzan.
"At 1-0 we were on the front foot and we were trying to get the second.
"But we have not won in a while so there wa maybe a bit of anxiety in our play.
"The second half was not as fluent as we'd have liked but the spirit and determination meant we were able to see it through."
Agnew said he was eagerly anticipating a "massive game" on Sunday against Manchester City, but was not looking beyond Sunday's match at the Riverside.
Boro trail Hull City by six points with four matches remaining, all against top level opposition, but the Teessiders will not be short of confidence after clinching the double over David Moyes side.
There is also the factor of City having a Manchester derby against United to negotiate first.
"It's a massive game on Sunday," said the ex-Hartlepool United assistant boss. "If it goes our way, who knows?
"City have a tough match against Manchester United,
"But Manchester City is our next game and that's the only game we are looking at."
Agnew defended his decision to choose Cristhian Stuani ahead of Adama Traore, who stayed on the bench.
"Cristhian scores goals and we are in a position where we need to score goals," said the manager who was happy with the finish from De Roon.
"It was a great goal, a fantastic pass from Adam Clayton, a good forward run by Marten and he did well."