But he warns they must not relax.
Karanka said: "We knew we had three important games and for that reason, we needed to have the squad as soon as possible.
"We knew that games like West Brom, Sunderland - maybe not Stoke - but all of them were our rivals in the league and for that reason to be in the table with five points is really important for us.
"Now it's Crystal Palace and there are another three points [at stake] and now we are in a really good position.
"But I don't have to forget in one week, two weeks, everything can change. For that reason, we have to forget the past, we have to focus on the next game, and then on the next one and the next one."