Who was former Burnley boss Steve Cotterill's best signing?

And one particular purchase as Burnley boss goes down as one of, if not the best acquisition of his managerial career so far.

Cotterill had great success with his dealings at Turf Moor.

He rebuilt a squad that had only eight players when he arrived in the summer of 2004, bringing in John McGreal, Frank Sinclair, Michael Duff, Micah Hyde and Danny Coyne instantly, before, among others, landing an 18-year-old Gary Cahill on loan from Aston Villa.

After the sale of Robbie Blake, he replaced him with Ade Akinbiyi.

After the sale of Akinbiyi, he brought in Andy Gray.

And when he left the club in November 2007, he left players like the skipper Steven Caldwell, Clarke Carlisle, Duff, Blake, Joey Gudjonsson, Alan Mahon, Wade Elliott and Stephen Jordan, who all played a big part in winning promotion to the Premier League under Owen Coyle in 2009.

But one stands out above all the rest, at all the clubs he has managed.

Graham Alexander signed from neighbours Preston for £200,000 in September 2007, and would only play for three months under Cotterill.

However, in 2008/09, he would go on to play all 61 games as the club reached the Carling Cup semi-finals and promotion via a Wembley play-off final.

He graced the Premier League as a 38-year-old, playing 33 of Burnley's 38 games, and passed the 1,000-game mark as a Claret under Eddie Howe in 2011, before rejoining North End.

And Cotterill feels he was the missing piece of the jigsaw: "The best signing I made for the club, and arguably one of the most important signings I made in my career - and I have been quite lucky with this, because I feel I made a lot of good signings at different clubs - was Grezza.

"For me, the signing of Graham Alexander was the best one, for £200,000.

"This is what I mean about my relationship with Barry Kilby, Grezza was 36, right back and sub for Preston, and couldn't get a game.

"I said to Barry I wanted to sign him, he said 'he's 36 now, why would we pay £200,000 for him?'.

"I just had a feeling about him, and Barry asked what that was, but I didn't want to tell him until we'd signed him.

"I told Barry to just trust me, and he did, we signed him, and I didn't tell Grezza at the time, but when he'd signed and we walked out at Turf Moor onto the pitch, I said I was going to play him central midfield.

"It's funny, at the time it took him back, he wasn't quite sure about that, but he was absolutely brilliant.

"He could run the game from that position, he was a fantastic professional."

Many players spoke of the influence Alexander had at Turf Moor on and off the pitch, and Cotterill added: "I saw the influence he had on the younger players, Michael Duff, Wade Elliott - he affected all those players, about being a great professional.

"It was no coincidence he carried on playing until he was 40.

"I think, when I look back, and there's been some brilliant signings - Luke Ayling at Bristol City who will go on and play in the Premier League with Leeds, Luke Freeman...

"I would say the most influential has to be Grezza, close run with Aaron Wilbraham, who I signed at 35 for Bristol City, who had an influence on all the younger players, with Wade, who'd learned from Grezza.

"Aden Flint, Derrick Williams, Ayling, Freeman, Joe Bryan, Bobby Reid...

"They were influenced by Wade, who had been influenced by Grezza.

"Grezza was almost the missing link at Burnley, and with Grezza we had David Unsworth, who was another good professional.

"Those two were really good in and around the younger lads, and have both gone on to have good coaching/managerial careers."