The Nigeria international has impressed during his brief time at Stamford Bridge with two excellent substitute performances, and he is now expected to go in to the Blues' starting line-up for Tuesday night's Capital One Cup clash against Wolves.
"He's young and he'll still improve and develop but he's an exciting player that I tried very hard to sign, not just this year but previously as well, years ago," said Di Matteo.
"He's a player I like very much and he will have a big influence in our season. He's strong at holding the ball, his dribbling ability is very good, he can go past defenders, which not many can, and he's got the pace as well.
"He's very good at making runs in behind, he's a very good player. It's good that nobody else noticed."