Returning to the club which he served both as a manager and player, Rosenior saw his Chelsea players earn a 4-0 win on the night, with Pedro Neto scoring a hat-trick.
The Blues manager said afterwards: "I think the overall positive thing was the application of the team. I thought our pressing, our intensity, our work rate, and Pedro exemplified that to be honest, that's why he scores the goals that he does.
"I'm very lucky to have such talented players and what I'm really realising quickly is that they are not just good players, they’re outstanding professionals. I felt it was a really professional performance tonight against a very good team who are pushing for the Premier League.
"This was not an easy game and some of our football was everything I want to see, but before that, the values of what the team stood for tonight made me a very happy coach."
On Mamadou Sarr's debut, Rosenior also said: "Mamadou was everything that I expect.
"I know Mamadou so well and I think his acclimatisation and adaptation process will, hopefully, be fast because he already understands how I want to play.
"But I don't want to single a player out as I felt the whole team, from Alejandro Garnacho's energy, pressing and running, to Liam Delap, Estevao, the midfield players, the back unit, Rob Sanchez, I felt it was a really strong team performance. That is what makes me so happy this evening."