IT was the summer of 2012 and the mood in Derby was not good.

“Gutted,” one fan said.

“God awful decision by Derby,” added another.

“Just when we thought it was all slotting into place, they go and sell our best player,” said a third.

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Controversially, Derby County were on the verge of selling their captain, Jason Shackell, to Burnley for a fee of around £1.1m.

“Shackell is the sort of player that we need,” another Rams supporter said. “Whatever Burnley buy him for, he’ll be worth every penny. Just like he was to us.”

On Saturday, Shackell was announced as man of the match as the Clarets beat reigning Premier League champions Manchester City.

City pressed and pressed, but could find no way through.

Aided by Michael Duff and the rest of the Burnley defence, Shackell put his body in the way time and again.

A tackle on Edin Dzeko denied the Bosnian a seemingly certain first-half goal, after David Silva had delivered the sort of first time, defence splitting pass that fellow Spaniard Cesc Fabregas had memorably produced for Chelsea at Turf Moor in the opening game of the season.

If tiki-taka was new to Burnley in August, by now Shackell was wise to it.

Shackell is the Clarets’ captain, but he has rarely made the headlines this season.

Perhaps the most notable story about him was the poll that voted him as the fifth most attractive player in the Premier League – and also comically asserted that ‘divorcees love Danny Ings’.

But Derby fans were not worried about their team becoming that little bit uglier.

They knew that Shackell’s departure would damage their chances of success, and so it proved.

Yes, the Rams may be challenging for promotion now, but they remain in the Championship a year after Burnley ascended to the top flight.

A mistake from a centre back ultimately cost them victory in the play-off final against Queens Park Rangers.

The Clarets’ survival hopes are still firmly in the balance, but that they are in this position at all is in part down to Shackell.

He is Mr Dependable, the defender who has started Burnley’s last 112 league matches.

Only injury at Newcastle United on New Year’s Day ended a run of more than two years without missing a single minute of action.

The man who signed him, Eddie Howe, departed for Bournemouth only a few months after Shackell’s arrival.

But the defender soon became the rock at the heart of Sean Dyche’s new and improved back line.

Throw in a goal in Burnley’s first win over Blackburn Rovers in 35 years, and Shackell’s impact with the Clarets has been immense following an era when defensive solidity was not always the club’s biggest strength.

Even if Burnley go down this year, one season in the Premier League will have been worth around £120m to them.

With more performances like the one Shackell produced on Saturday, the Clarets may yet earn a second campaign in the top flight.

“He’ll be worth every penny,” that Derby fan said three years ago.

You can be pretty sure they were right.