Guus Hiddink fears Everton's Tim Cahill will thwart Chelsea in FA Cup final
Hiddink saw Cahill thrive during his spell as Socceroos coach at the 2006 World Cup, highlighted by his two-goal performance in the famous come-from-behind win over Japan.
The pair built up a mutual respect that has shone through in the lead-up to the final at Wembley, after which Hiddink returns to his full-time job as Russian coach.
Cahill still regards his former coach as a "genius" while Hiddink isn't looking forward to having the midfielder on the other side.
"Of course I know Tim from my Aussie period," Hiddink said.
"It was beautiful to have him in my own squad but having him as an opponent is not nice. Everton are very organised and he is a player who can make a big impact.
"He is a wonderful talent, very sharp and dangerous around the box."
Cahill will become only the second Australian behind Craig Johnston to appear in two FA Cup finals, having played for Millwall in their loss to Manchester United five years ago.
Millwall, then in the Championship, were not expected to trouble mighty United and they didn't, losing 3-0 in a valiant display.
Man of the match that day was United's 19-year-old winger Cristiano Ronaldo, who has since gone on to become the world's best player.
It was also the start of an amazing journey for Cahill. He was snapped up by Everton before the next season and his transition to England's top flight was seamless.
Next came his World Cup heroics.
Now, Cahill is heading to Wembley again with a whole new set of expectations.
"It was some experience with Millwall," Cahill said. "But this time it is an experience where I know that we have a massive chance of winning. Hopefully this time I can go one step further."
Under manager of the year David Moyes, the Toffees have defied the odds in reaching the final and securing a Europa League berth this season.
Their campaign has been rocked by injuries, even forcing Moyes to use Cahill as striker.
"We have got to go into the game thinking that we can do it," Cahill said.
Despite his admiration, Cahill will be desperately trying to deny Hiddink a last chance at silverware with Chelsea.
The Dutchman has admitted he will be haunted by a nagging sense of regret when he walks away from the club, having already lost out narrowly in the Premier League and European Champions League.
"I am very determined that we should win the FA Cup," said Hiddink, who made an instant impact when he was brought in as a replacement for Luiz Felipe Scolari.
"I want to leave having won something."