If Sydney FC triumph in enemy territory over Melbourne Victory in Sunday's blockbuster Hyundai A-League Grand Final, there'll be an NRL coaching legend quietly celebrating the success of one of his proteges.
The name Wayne Bennett might be synonymous with League, but the multiple premiership-winner has also had a part to play Arnold’s coaching success in the A-League.
Arnold famously picked the brain of Bennett in the lead-up to the Mariners' drought-breaking Grand Final triumph in 2013.
With mental demons following their Grand Final loss to Brisbane Roar two years earlier still fresh in the minds of some players, Arnold turned to the seven-time premiership winner.
Arnold took Bennett’s advice to relax his jittery squad the night before the big day.
The Mariners playing group got together and watched a funny DVD in the team hotel. It gelled the squad and relaxed them perfectly.
A day later, the yellow and blue walked out onto Allianz Stadium against the imposing Wanderers and their noisy fans, and smashed them.
Arnold and his Mariners won 2-0, deservedly so too. Big Patrick Zwaanswijk and Daniel McBreen with the goals to silence an estimated 35,000 travelling red and black fans.
Finally lifting the championship trophy and in dong so banishing their Brisbane nightmare from two years prior was as sweet as it gets.
And it’s why the Sky Blues boss won’t hesitate to call on Bennett’s big-game experience if he needs some advice before the decider against Melbourne Victory.
The pair have been friends for just under a decade, when they first met as Arnold did some goal-kicking training with Brisbane Broncos skipper and great Darren Lockyer.
They have kept in contact ever since.
If “Arnie” has a problem, he seeks out Bennett’s counsel for a trusted opinion.
"I don't pick the phone up every week, but if I have a dilemma I know that he's there," Arnold told the Sydney Morning Herald.
"I know he's there for me, and I know he genuinely cares for me."
The Sky Blues boss has been fortunate enough to have some excellent mentors during his coaching career.
Names like Guus Hiddink and Pim Verbeek immediately jump out. But Bennett’s influence has been key.
Like Bennett, Arnold maintains a public profile as ‘Mr Grumpy’.
He gives off gruff exterior, at war with everyone from referees to football officials to the media.
You only have to ask his players though and they will tell you about a man who always backs them to the hilt, a leader and a father figure.
It’s also something Bennett has been known for throughout his 28-year top-level coaching career.
For Sydney FC and Arnold, having Bennett's influence behind the scenes could just help the Sky Blues get over the line against the highly talented Victory.
If so, one of the NRL's true greats will have helped shape the fate of another A-League Grand Final featuring coach Graham Arnold.