Delap played for Rosenior at Hull City and after scoring in defeat at Fulham last night, he discussed the new manager's arrival.
He said, "Everyone’s excited to work with the new manager. Enzo’s (Maresca) left, but we just have to work even harder under Liam and see what his ideas are.
"I know him really well and he’s a top manager so hopefully he can help the players and we can just start from that. I think he’s a really exciting young manager and he loves to play football.
"I know he’s got unbelievable passion in wanting to be a manager, so hopefully he can bring his ideas into our style of play and help us as much as he can."
On scoring his first Premier League goal for Chelsea, Delap added: "It’s been a difficult start for me with a few injuries and then it’s always difficult to get sharp and get going.
"I’ve got to a period now where I’m starting to feel good, so hopefully that can carry on and continue until the end of the season."