Mark Jackson wants Leeds United's Under-23s to 'sharpen up' amid praise for match-winner
The Whites edged out the Rams at Loughborough University on Friday night in front of a crowd of around 300 supporters.
United fell behind early on in the Premier League 2 encounter thanks to an Osazee Aghatise strike but wide man Crysencio Summerville levelled a short while later with a fine solo run.
Derby again took the lead through Connor Dixon before being pegged back once more by Leeds striker Sam Greenwood on the half hour.
The game ebbed and flowed in the second period - Aghatise hitting Kristoffer Klaesson's post after bursting through the closest moment to a fifth goal.
Half-time substitute Joe Gelhardt, though, had the decisive say 18 minutes from time as his thunderous effort from outside the box found the bottom corner of Harrison Foulkes' net.
The goal was enough to seal all three points for the Whites as County were reduced to 10 men late on but boss Jackson was left wanting more from his outfit defensively.
Leeds were forced to fightback from behind twice and the performance followed up the concession of four goals against Tottenham Hotspur on Monday.
"We showed good character but I said at half-time we need to sharpen up defensively," Jackson told the YEP post-match.
"We need to learn and can't be as open and conceding as many chances and goals going forward. It's something we have to look at. It's not just on the defenders but it's on us as a team.
"It's one thing we need to look at going into the coming games. We always pose a threat going forward but we have to have that mindset and be able to switch to defending better."
Asked about Gelhardt's strong performance after stepping off the bench, he added: "He gives you that does Joffy. He can look after the ball, he's a strong player.
"He gave us that focal point and it was on him to hold the ball up. He created an individual goal out of nothing but that's what Joffy can do.
"We have players in the team who can create goals and can go forward and create chances.
"Overall we are pleased with the victory but we know there are still things we can improve on and get better."