Barkley produced some impressive moments in the 1-0 victory over Southampton on Saturday, which eased any lingering relegation worries for the Toffees.
The 21-year-old’s substitution with 20 minutes to go brought a negative reaction among the home fans at Goodison Park, and Republic of Ireland international McCarthy reckons Barkley’s performance was the key to Everton’s victory.
“I think Ross was different class,” he said.
“I thought he worked really hard for the team and was a real nuisance driving at people and it was brilliant to see him high in confidence having been away with England.
“Ross is a good lad and has his feet firmly on the ground and has a lot of people at the club looking after him.
“He won’t get carried away. We have a lot of characters, a lot of experienced heads in the dressing room and there is no better place to be for him.”
Everton achieved what they were unable to do earlier in the season and ground out the victory to make it three successive wins, moving them to 11th in the Premier League table.
With nothing to play for in their remaining seven matches McCarthy believes the motivation is to remain unbeaten until the end of the campaign.
“We want to kick on, go on a winning run and finish the season strongly,” said McCarthy.
“We have won three games and we want to go unbeaten until the end of the season, although that is easier said than done.
“There has been a big improvement. So far, so good, but we won’t get carried away.
“The most important thing was to get three points and dig in deep to secure it with a clean sheet.”