Adam arrived in the summer from Blackpool.
Reina told liverpoolfc.tv: "It's a case of so far, so good for Charlie at Liverpool. The team is improving all the time and Charlie is also getting better.
"I probably analysed him more than most before he signed because I knew how dangerous he is at free-kicks.
"He also has great deliveries. Charlie is a great player to have in the squad and he can become very important for us.
"He was also Blackpool captain and that means he can handle responsibility."