The former Marseille winger contributed the opening goal and three assists to the Magpies’ 4-1 victory over League Two Northampton at St James’ Park to leave the former England boss purring.
McClaren said: “I thought he was very good when he came on, even for 10 minutes, at Old Trafford and showed his quality. He has been terrific in training.
“You never know what to expect – you have seen a lot of him, but he is confident, he has got great ability, but the key thing is he can score and he can assist, and that’s a big asset for us.
“Great delivery – that’s going to be vital, very important. You can have tall men and all the good headers in the world, but if you don’t get delivery, you get nothing.
“You saw tonight, his delivery is excellent, so he can score and assist and do the work. That’s what he can do.
“What pleased me tonight was that attacking-wise, we looked more of a threat than we have done in previous games, and the squad has come together very nicely – and I emphasis the word ‘squad’.”
Thauvin announced his arrival within three minutes of his home debut when he stabbed home Massadio Haidara’s back-post cross, and then turned provider to allow Siem de Jong to make it 2-0 with the game just five minutes older.
Marc Richards’ 10th-minute penalty reduced the deficit, but second-half goals from defenders Daryl Janmaat and Mike Williamson had the victory wrapped up with almost half an hour remaining.