Boro head for Sheffield Wednesday on Saturday having failed to score in each of their last six Sky Bet Championship games, a run which culminated in last weekend's 0-0 home draw with Leeds.
Karanka told the club's official website, www.mfc.co.uk: "We have to play like we did in the last game - but this time to score.
"The message I told them after the game is that if we play the way we did against Leeds and Blackpool, the goals will arrive. We need to keep working and believe in our way.
"I am more confident this week because the way we played last weekend was good for me. If we play this way, we will win the games.
"The players have worked very well in training and I hope this Saturday is the day we can score the first goal."