Oxlade-Chamberlain joined Liverpool in a £35million deal over the summer from Arsenal.
After an indifferent start, the winger is starting to settle at Anfield and offered an encouraging performance in the 4-0 win over Bournemouth on Sunday.
The 24-year-old heads back to face his old club tomorrow at the Emirates (7.45pm).
Klopp still thinks Oxlade-Chamberlain has some way to go with his development.
However, he admits he would be as good as Messi if he had already fulfilled his potential.
“He is still a young player,” Klopp said.
“It’s unbelievable but he has 10 or 12 years yet to come in his career!
“If he was already complete by now then he would be Messi!
“He is the only player who was complete at that age.
“Now he can improve and that’s fine.”
Liverpool are currently fourth in the table, with tomorrow’s opponents Arsenal fifth.