The Uruguayan star capped a fantastic display with a sublime 25 yard free-kick, 13 minutes from the end last night.
"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. The main thing is he's getting better every single day."
Karanka went on to say how his on loan star changed the game for his side:
"Gaston 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."
Ramirez moved to Middlesbrough from Southampton on loan in January, and with his contract expiring at the end of the season, he would be a fantastic acquisition for the North-East outfit.
In his 11 appearances for Middlesbrough, he has scored six goals, while also registering an assist, and has been pivotal in Boro's rise up the league table.
Earlier on in the month, Karanka missed the home loss to Charlton, following a training ground bust-up. The writing seemed to be on the wall for the former Real Madrid assistant, but he returned the following week, and in an incredible turnaround, has overseen his side win three games on the trot.
The Middlesbrough manager was adamant that his side must focus on their own game, rather than worrying about results of other teams:
"If the other teams are losing and we are losing it's all the same. It depends on us. Once again it's about us and that's the main thing. We have a game in hand, we need to keep playing as consistently as we are and we are in a really good position. We have to keep going because this league is really tough."
Next up for Middlesbrough is a visit from mid-table Preston North End, as they look to leap frog Burnley at the top of the Championship.