The BT Sport pundit thinks Celtic could have squeezed more out of Arsenal in negotiations.
Tierney made the move from Glasgow to London for £25m, making him the most expensive export in the history of not just Celtic, but Scottish football too.
It was a major deal but for Hartson, Arsenal have won a watch, with the Hoops missing out on an even bigger windfall.
As quoted by The Scottish Sun, the former striker said: “At £25million, Celtic got good money for Tierney. But if you look at it, and I am being honest here, then Arsenal probably got him on the cheap.
“Look at the fact that Manchester United paid £50m for Aaron Wan-Bissaka, and average players are going for £30m or £40m down south.
“Tierney is certainly not an average player. I thought Celtic could have held out for another £5m or so.”
Did Celtic sell themselves short?
The way negotiations panned out between the two sides, £25m always seemed like a good compromise. The Gunners had failed with a number of lower bids and Celtic set their price.
If they’d gone for £30m there’s every chance the move would have fallen apart.
The Hoops are also coping without the Scotland international well since his departure, with the club perhaps realising he is not as integral to their play as £25m is to their future plans.
Ultimately it made sense for all parties. Celtic get a record fee, Tierney gets his big move and Arsenal get a player from a football market that is likely a bit underrated, to their financial benefit.
Compared to the crazy deals that occur in the English Premier League, the Gunners did indeed get a good deal.
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