The new Bayern Munich boss has slammed the Blaugrana president for attempting to paint him in a negative light through the media, saying he "crossed a line"
The former Blaugrana boss left Camp Nou last summer and embarked on a 12-month sabbatical from football in New York - the same city in which Vilanova received treatment in his battle against cancer.
But Guardiola has been angered by several stories that have appeared in the press suggesting the pair were not in contact during his illness because of a breakdown in their relationship, an accusation the 42-year-old says is fictitious and instigated by Rosell.
"This year there have been too many times when they [Barcelona & Rosell] crossed the line. Using Tito Vilanova's illness to hurt me, that I will never forget. I saw Tito Vilanova in New York, and if I didn't see him more it's because it was not possible for me to do so.
"Do I have to justify wanting a partner I've had for so long and helped me so much to do well? That was something in very, very bad taste."
Tensions between Rosell and Guardiola appear to stem from the current board's dislike of the regime that appointed the now Bayern Munich boss to the Camp Nou helm, which included former president Joan Laporta and Barca great Johan Cruyff.
And the Bavarians coach has ordered his old club to bring an end to their apparent smear campaign against him and allow him to focus on his new life in Germany.
"Let me enjoy my job and these players that Bayern gives me to do the best I possibly can," he added.
If any of the things I've said is not true, come out and rebut it. But it has to be them (Rosell and his board), not intermediaries or Barcelona messengers, them. They have to focus on making their team work and leave me alone."
Guardiola spent a success-laden four years in charge of Barcelona, working under Rosell in his final season at the club.