The double from Belgium bit-part striker Batshuayi could be a turning point, said Cahill.
“I’m sure he feels he’s got things to prove and, as a player, that’s exactly how you respond,” said the centre-back.
“He’s come on and changed the game for us. For strikers it’s all about scoring goals.
“It’s the same for us defenders. I scored eight goals last season and I feel like I can’t get a sniff at the minute.
“As soon as you score one goal you feel like every time you go up you are going to score so I’m sure it’s the same feeling for them.
“Those two goals will do him the world of good.”