Neil Lennon was instantly impressed by David Turnbull two years before eventually taking the midfielder to Celtic Park, according to Stephen Craigan.

Now the Celtic boss has to decide whether to put his undoubted faith in the 21-year-old for Sunday's William Hill Scottish Cup final against Hearts or stand by the players who have helped the club win the previous 11 domestic trophies.

Turnbull has lit up Celtic's play in the past two games, with victories against Lille and Kilmarnock providing respite after a run of two wins from the previous 12 matches.

The Scotland Under-21s player scored his first goal for Celtic and set up two more having been handed starts after a series of substitute appearances following his move from Motherwell earlier this season.

Lennon first picked out Turnbull's talent while manager of Hibernian as he watched the club's under-20s side, featuring the likes of Ryan Porteous and Jamie Gullan, beat Craigan's Motherwell before they collected the Development League trophy.

Craigan told the Football Pass YouTube channel: "I was talking to Neil while the players were getting their medals and he actually said to me quietly: 'Who's your number eight? I really like him'.

"I said: 'It's David Turnbull and you need to keep your eye on him because he's a top player'.

"He said: 'Even for the result, he was the one player that stood out for me'.

"Coaches and managers keep an eye on players so he would have been interested to see when David stepped into the Motherwell first team and how he would react.

"To get 15 goals from November 2018 to May 2019 from midfield as a 19-year-old was incredible and eventually Neil took him to Celtic."

Craigan believes Turnbull is the best young player he has worked with.

"Nothing fazed David," the former Motherwell skipper added. "Going from 16-year-old to playing under-18s, under-20s, playing in Motherwell's first team, and watching him the last couple of games for Celtic, he still plays the same way.

"He wants to get on the ball, he wants to find pockets of space, he wants to affect the game going forward, he wants to get shots off. He is probably a little bit away fitness wise, he will get sharper and stronger, so the only way I see him going is upwards."

Lennon now has to decide whether to stick with Turnbull, Ismaila Soro and goalkeeper Conor Hazard after they came in two games ago at the expense of Scott Brown, Tom Rogic and Ryan Christie and experienced keepers Scott Bain and Vasilis Barkas.

"Neil has got a dilemma, no doubt about it, but it's probably a dilemma he has been looking forward to over the last couple of months because he has been picking teams and they have been losing games," Craigan said.

"They have now won back-to-back games and I can imagine if Soro and David Turnbull don't start the game, I think there could be another protest outside Celtic Park.

"I think them playing in the final and potentially winning could be the making of them, because when you go to Celtic it's all about winning trophies. This could be a real turning point for those young players to really establish themselves."

Craigan also accepts that might be unfair on the players who have taken Celtic to the brink of a fourth consecutive treble.

"Everyone is pointing to Scott Brown and I think it's a bit unfair on Scott Brown," he added.

"I think he should have been managed better over the last 18 months, he shouldn't have been playing every single game.

"When you get older, your recovery time can take a little bit longer, you are maybe not as fresh in games. I think he's been taken off in every Europa League group game he started. That tells you he is not where he wants to be.

"You only have to look at Rangers and Steven Davis. Steven Davis is six months older than Scott Brown, yet he hasn't had as many starts, he hasn't been taken off in as many games, and he is still influencing games. Steven Gerrard puts him in in the big games."