There was surprise when returning Chelsea manager Jose Mourinho allowed Lukaku to go out on loan and that has been highlighted by the fact his league tally is already more than all the strikers at Stamford Bridge put together.
And don't forget, Mourinho is not believed to be a big fan of Demba Ba, so he must be surprised that Lukaku is lighting up the Premier League.
Roberto Martinez: "Lukaku is a young man who has everything as a striker.
"Sometimes you see a number nine who is powerful and has a great physical presence - what Romelu brings is a real awareness around him.
"He is technically really gifted when he has his back to goal and that was a focal point today.
"He is a great goalscorer. He looked like a player who felt at home.
"I want him to enjoy his football, I want him to develop and become as good as he can.
"You need to remember how many strikers Chelsea have.
"You need to mention Samuel Eto'o's record, Demba Ba's record and Fernando Torres' pedigree, you are talking about a squad which has phenomenal talent up front.
"I thought we were very good in the first half.
"We defended extremely well and kept Newcastle to very little threat and from that point on some of the attacking play was fascinating to see the link-up play up play with Romelu, Ross and (Kevin) Mirallas.
"Once that happens you can score too many goals. Sometimes you go into half-time with a one-goal lead and that allows you to keep the tension.
"It was normal you are going to get a reaction in the second half.
"It was a completely different performance. We showed style in the first half and grit into the second."