Vettel called Karthikeyan an "idiot" after their collision as the Red Bull man was lapping his HRT. The incident cost Vettel fourth place.
Speaking to the Hindustan Times, 35-year-old Karthikeyan described Vettel as "unprofessional".
He added: "For a world champion to say things like that is really shameful."
Vettel ended up finishing 11th in Malaysia after dropping down the field with damage caused in the collision with Karthikeyan.
The result leaves the man, who has won the title for the last two years, sixth in the championship, 17 points adrift of the leader, Ferrari's Fernando Alonso.
In German, Vettel used the word "gurken" - cucumber - to describe Karthikeyan's driving - a common insult used about bad drivers on the road.
Karthikeyan said: "It is really unprofessional. For a driver who has achieved so much to take out his frustrations on me just because he is having a difficult year is really sad.
"One does not expect a professional sportsman to be such a cry baby."
Speaking to the Hindustan Times, 35-year-old Karthikeyan described Vettel as "unprofessional".
He added: "For a world champion to say things like that is really shameful."
Vettel ended up finishing 11th in Malaysia after dropping down the field with damage caused in the collision with Karthikeyan.
The result leaves the man, who has won the title for the last two years, sixth in the championship, 17 points adrift of the leader, Ferrari's Fernando Alonso.
In German, Vettel used the word "gurken" - cucumber - to describe Karthikeyan's driving - a common insult used about bad drivers on the road.
Karthikeyan said: "It is really unprofessional. For a driver who has achieved so much to take out his frustrations on me just because he is having a difficult year is really sad.
"One does not expect a professional sportsman to be such a cry baby."
