Marcos Alonso added a second-half free-kick to Batshuayi’s first-half double as Chelsea eased into the fifth round.
“We are talking about a powerful player because he is strong physically, and for sure he has a lot of space for improvement,” said Chelsea boss Conte.
“I don’t know if it was his best game, but it was very important for the team and for him. For the striker to score is very important for confidence.”
Batshuayi rounded off a superb move to open the scoring for the 2017 finalists after the home side had made a slow start before putting the finishing touch to another Chelsea break just before half-time.
Alonso’s free-kick, which took the defender to a career-best seven goals in a season, sealed the win for the home side with Newcastle unable to build on an encouraging opening 30 minutes.
“It was a good performance. It wasn’t easy because Newcastle prepared a very defensive game. When the draw faces you with another Premier League team it’s never easy,” added Conte.