David Unsworth admitted Everton Under-23s’ performance “wasn’t good enough” after the young Blues were beaten 4-1 at Derby County on Friday night.

Everton, previously unbeaten in Premier League 2, were the more progressive side during the first half at Pride Park and Ellis Simms’ superb solo effort gave the Toffees a deserved lead.

But Unsworth’s side were pegged back before the break when Louie Sibley rifled in from 20 yards.

Derby then struck three times without reply in the second half to run out comfortable winners.

Manager Unsworth says his team must learn valuable lessons after the defeat.

“We gave away poor goals and unfortunately the performance wasn’t good enough,” he told evertonfc.com.

“In the first half we were the better team. We played really well.

“They got back in it and got a lifeline out of nothing.

“In the second half, Derby have overrun us and deserved to win. We made sloppy mistakes which led to our downfall. 

“The players have got to take a lot of responsibility and I said to them after the game, that they need to think about where they believe they are, as opposed to where they actually are in their development.

“You always have to prove yourself and perform in this league. And they didn’t do that tonight.”

Shortly after Derby’s equaliser, Everton were dealt a blow when in-form forward Anthony Gordon was forced off with a knee injury.

Gordon had already produced a number of flourishes of class, with his feinting, swerving dribbles regularly forcing Derby defenders to retreat.

He was replaced on 40 minutes by another talented youngster, with 17-year-old Mackenzie Hunt making his first appearance of the season.

“I think it deflated the players to see Anthony go off,” Unsworth admitted.

“He has been our best player all season. He has been absolutely outstanding in every game for us.

“He’s hurt the back of his knee, but it doesn’t look like it is going to be a long injury.

“Mackenzie came on, though, and he will benefit from those minutes. He’s a player we believe in.

"He had a great start to his pre-season with us but then suffered a stress fracture. He’s been working hard with the fitness department and that time on the pitch will help him.”

Everton had been steadily building pressure before Simms’ opener 23 minutes in.

Unsworth’s team had penned the Derby defence back for extended periods, but without creating any gilt-edged goalscoring opportunities.

And the danger appeared minimal when Simms collected the ball 35 yards from goal.

But the striker showcased his impressive speed, power and composure to drive into the penalty area - leaving two Derby defenders in his trail - and place a precision finish past Rams stopper Jonathan Mitchell.

Simms almost had his second soon after, Mitchell producing a fingertip stop to keep out his goalbound header from Kyle John’s cross.

Everton continued to play on the front foot but, after a rare foray forward, Derby drew level 36 minutes in.

After being picked out Max Bird, Sibley lashed home from just outside the area. It was the home side’s first effort on target.

Derby were a different side after their equaliser, attacking with speed and purpose.

They went ahead just after the hour mark – striker Jahmal Hector-Ingram tapping in at the back post after a slick team move.

Hector-Ingram made it 3-1 from the penalty spot on 73 minutes after Everton goalkeeper Harry Tyrer was penalised for upending Archie Brown.

Joshua Shonibare then wrapped up victory for the home team nine minutes from time, finding the bottom corner with a powerful strike from 25 yards.

Everton remain in third position in Premier League 2, five points behind leaders Chelsea.

The Toffees will have the chance to close that gap when they face west London side at Southport FC next Saturday (2pm).