Huddersfield enjoyed the majority of the early possession but the home side looked dangerous on the counter-attack as Ramirez set Jordan Rhodes free – only for the striker’s shot to be tamely deflected into Steer’s arms.
And an exquisite turn in the box from the loanee midfielder outfoxed defender Lynch, to gift Boro the simplest of opening goals.
Having failed to score in his five matches for Southampton this season prior to his move to the Riverside, Ramirez netted his fifth and sixth goals in a Boro shirt, with two goals of Premier League quality.
Victory sees second-placed Boro secure three consecutive wins for the first time since December and they also have a game in hand on Burnley with seven matches left to play.
The Terriers meanwhile remain eight points above the drop zone in 18th and look to have ensured another season in the Championship.
Middlesbrough manager Aitor Karanka:
“Gaston Ramirez was the player who changed everything.
“For the first 25 minutes we looked as if we were playing for nothing. He was the difference between Huddersfield and us.
“I think it was his best game for us. He scored, he worked and he came up with an assist for the penalty – the things we expected when he came here.”
Huddersfield head coach David Wagner:
“The goals we conceded were too easy. Each of them were presents.
“We lost the ball too easily and were not able to keep it as long as we usually do.
“If you like to get a result against such a good team as Middlesbrough at this stage of the season – when they are very focused – then you have to make nearly everything right.”