Nico Rosberg believes Lewis Hamilton was "looking for some excuses" as to why he lost in Mexico when he stated that Mercedes had been "extra warm" to his team-mate.
Having wrapped up the World title in Austin two weeks prior Hamilton had hoped to chase the record for most wins in one season.
However, that came to naught in Mexico when Rosberg beat him to the chequered flag.
Hamilton later stated that Mercedes had "felt the need to be extra warm (to Rosberg)" following his defeat in both Austin and the Championship.
Rosberg reckons his team-mate was grasping at straws.
He told Press Association Sport: "I don't know what he really meant with that.
"He wears his heart on his sleeve, and in the heat of the moment after the race he was most probably looking for some excuses for losing the win right after winning the World Championship. Maybe that is how it came out."
As for Hamilton saying that his team-mate had not made an effort to congratulate him on winning the title, Rosberg blatantly said that is "not true."
The German said: "He said that? That is not true. It is on TV. I congratulated him right after Austin behind the podium and I have no problem with that.
"He deserves to win the title so I congratulated him and I will do it again here in the interview: 'Congratulations Lewis'.
"Lewis has done a great job and he has been better, but I was a bit more unlucky than he was with a couple of things."
The latest spate, which comes after months of calm at Mercedes, has Rosberg conceding that his relationship with his team-mat has its ups and downs.
"I don't want to describe our relationship. You can see it from the outside. It goes up and down, and it always will because it is an intense battle.
"We are battling for wins and championships so it is always going to be difficult."