Chelsea were forced to adapt after Palace were reduced to ten men, but Rosenior was pleased with how his side controlled the game and stuck to the plan.
The result made it four wins from five matches in all competitions under the new manager and six points from his first two league games.
"I think today was a huge test," Rosenior said. "I changed the shape and the performance made me very pleased. Ninety-five per cent of the press and the positioning was absolutely perfect.
"They're engaged and they believe in what they're doing. But it's only one game. We have to be consistent."
Chelsea took the lead in the 34th minute when Estevao punished a defensive mistake to score past Dean Henderson. After the break, Estevao turned provider as Joao Pedro doubled the advantage in the 50th minute.
Enzo Fernandez made it 3-0 from the penalty spot after a VAR review confirmed a handball, with Palace defender Jaydee Canvot avoiding a red card but not a booking. Chelsea were denied a clean sheet late on when Chris Richards headed home in the 88th minute.
Rosenior was not fully satisfied with the closing stages. "I wasn't happy with our last ten minutes," he said. "I felt we should have gone on to dominate the game further."
Chelsea now turn their attention to Europe, travelling to Napoli for a Champions League clash on Wednesday, with Rosenior again stressing the need to keep standards high.