Antonio signed from Nottingham Forest on transfer deadline day, and had to bide his time waiting for an opportunity.
This only came after an injury to Dmitri Payet, but in the weeks since he has done enough to show that he warrants involvement even when the Frenchman is fit.
Carroll singled Antonio out for praise when discussing the strength of the West Ham squad.
He said: "We've got most of our players coming back fit now which is great. The lads who have come in, like Michail, have shown their quality and that they should be in the squad.
"It's a great squad to be involved in when everyone's fighting for places."
Antonio set up the winner for Carroll to score against Southampton, so he is right to be appreciative of his impact.
Carroll netted only his second league goal of the season in the win, lifting the Hammers up to seventh place in the process.
The team have struggled with injuries over the course of the season so far, and their patience with Antonio has inadvertently worked in their favour, in that when they needed him, he was able to galvanise the side with a fresh approach.
When teammates Sakho and Valencia are back at full speed again, Carroll may find that competition for places works against him - or in his favour if it causes him to lift his game.