Ramiro Funes Mori played 74 minutes as Antony Evans' second-half goal secured Everton Under-23s' progression to the knockout phase of the Premier League Cup at Oakwell.
Barnsley fielded no less than six players with first-team experience this season but the Blues thoroughly deserved the spoils after a dominant second-half display.
Mason Holgate played the best part of an hour for Everton while, having managed 45 minutes against Arsenal last week, Funes Mori got another good run-out under his belt as he stepped up his recovery from a serious knee injury.
The hosts enjoyed the better of the exchanges in the first period and Mateusz Hewelt was certainly the busier of the two goalkeepers, the Everton youngster beating away a well-struck drive from Brad Potts and a powerful Jason McCarthy header.