Lewis impressed in defeat to West Ham yesterday.
"I thought Adam was excellent," Critchley told liverpoolfc.com.
"He provides something different with his quality. From the middle of the pitch he can open up a defence. His energy was very good.
"I don't think it harms him playing both left-back and midfield at the moment. He's similar to Trent [Alexander-Arnold] in that way.
"He's capable of playing both and his versatility could be a real plus for him going forward."