Former Don Stuart Duff played alongside Jonny Hayes when he was an unknown quantity in Scotland’s top flight.
And, although Premiership defences may be well aware of the Irishman’s quality upon his return to Aberdeen, his old team-mate says they won’t find it any easier to stop him.
Hayes has returned for a second spell with the Reds after three years with Celtic.
Duff played alongside the 33-year-old at Inverness Caley Thistle during a loan spell in the 2009-10 campaign and for all of the following season.
The Caley Jags won the First Division in 2010 in what was Hayes’ first season in the Highland capital.
Making the step up to the top flight the next term, Duff believes he took many Premier League defenders by surprise.
The former Dundee, Aberdeen, Cove Rangers and Inverurie Locos midfielder said: “There were a few Irish guys at Inverness at that time Adam Rooney, Richie Foran and Jonny so there was a good core of the squad there.
“Their work ethic was terrific and the more they trained the better they got.
“I played behind Jonny quite a few times at full-back or alongside him in midfield and he was a terrific outlet for you, he gives you great energy down either flank, he gets crosses in and he can finish.
“He was always up and down the park and I think he’s got better with age as well, like a fine wine almost.
“He’s a top player and I’m not surprised by the career he’s gone on to have and he’s got a lot more still to offer at Aberdeen.
“At that time and that season (at Inverness), I suppose he was a bit of an unknown quantity, but we all knew what he could do training with him every day.
“He’s such a great outlet for teams, particularly if you’re under pressure, he can run 30 or 40 yards get the team up the pitch and create something.
“He’s a very direct player with that sharpness and speed and I’m not surprised with how he’s gone on since Inverness.
“I’m sure Derek McInnes and Aberdeen will manage to utilise him to good effect again this season.”
Hayes left Inverness in 2012 to join Aberdeen in 2012 before departing for Celtic five years later.
Duff, who played for the Dons from 2007 to 2010, believes bringing him back to Pittodrie this summer is a great coup for the Reds.
The 39-year-old, who now plays for Banks o’ Dee added: “I think it’s a superb bit of business for Aberdeen and for Jonny.
“I think Jonny still has a lot to offer, he’s played for the champions for the last three years and has been playing with a slightly better quality of player which I think will have helped him.
“To bring him back to the club is a very good signing and a marquee signing for Aberdeen.
“Jonny can play three or four positions pretty comfortably so I think he’s a terrific addition to Aberdeen’s squad.”
With Aberdeen’s finances significantly impacted as a result of the coronavirus pandemic Hayes’ return was only made possible because he has agreed to defer his wages for a year.
Duff wasn’t surprised by the gesture and said: “It’s a great gesture, but when I first read about it I wasn’t really surprised because that’s the type of character Jonny is.
“He plays for the love of the game and to do that on the behalf of the club is a very bold statement from him and it shows he just wants to come back and enjoy his football.
“Football is a short career, but the money is not the be all and end all and for Jonny to make this type of statement in these tough times and help the club is testament to Jonny as a person and a player.
“It shows that his main aim is just to come and play regularly at Aberdeen after being in and out of the team a bit at Celtic.
“For him to do what he has is something I’m not that surprised by because he’s a terrific lad on and off the park, but it’s still a great gesture and I’m sure he’ll do very well in his second spell with Aberdeen.”