The memory of Guus Hiddink's three-month spell in charge of Chelsea in the spring of 2009 underpins the club's decision to court him again, and explains why the Dutchman would consider putting retirement on hold to work for one of the most ruthless men in world football.
Hiddink delivered the FA Cup during his brief time at Chelsea, but more importantly did enough to convince Roman Abramovich that he was the ideal man to deliver both the trophies and the elegant football he craves. Nothing that has happened since has dissuaded him from this opinion.
Hiddink's impact in 2009 was immediate – he revived the flagging spirit and confidence of the star players who had lost their way under Luiz Felipe Scolari by bringing greater discipline to the squad and greater intensity to the training sessions.
He also struck the right balance between banter and business with the players, who in turn responded in style. When Hiddink came in, owner Roman Abramovich feared they might finish outside the top four. In the 13 Premier League games that followed under Hiddink, Chelsea won 34 points from a possible 39 and lost just once. They ended up 20 points clear of fifth-placed Everton, who they beat 2-1 in the FA Cup final, Hiddink's final game in charge.
Captain John Terry, one of several senior players who asked him to stay on, described Hiddink at the time: "He's full of fire and dignity."
The defender added: "If you make a mistake in training, or in a game, he will scream and shout at you. He gives you a kick up the backside and sometimes as a big player you need that. Certainly, since he came in we're fitter, sharper and looking a much more organised side."
Abramovich will be hoping Hiddink has a similar revitalising effect again. But this time the Dutchman will also be able to exert greater influence in terms of building the squad to his specifications. In 2009, he arrived after the winter transfer window had closed.
Hiddink said two years ago: "When you want to compete, you have to renew your squad almost every year. Ageing players, around 30 and older, every now and then need to be released. They can still perform but you might face all kinds of trouble if all the players get injured. It's difficult to come back, as a young man normally might."
With Abramovich prepared to back his new manager in the transfer market this summer with money made available for new signings, Chelsea hope the Hiddink effect will be doubled – his experience in the transfer market adding to his impact on the training ground.
One game in particular stands out of the Hiddink era – Chelsea's controversial elimination to Barcelona in the second leg of the Champions League semi-final. Norwegian referee Tom Henning Ovrebo went into hiding after receiving death threats from Chelsea fans for his controversial handling of the game.
But were he to put his big bald head above the parapet now, he might be due a vote of thanks from the Chelsea fraternity rather a volley of abuse, for it was that night that the fates of Chelsea and Hiddink became inextricably linked.
Ovrebo denied Chelsea four penalty decisions, and they went on to lose the semi-final to Andres Iniesta's injury- time equaliser, eliminated on the away goals rule. Chelsea have not come close to matching the intensity and unity of that night in the Champions League under Carlo Ancelotti, and that is the key reason he has been sacked and Hiddink lined up to replace him.
Barcelona have since gone on to win the Champions League final twice, and have been hailed the greatest team in the history of the game.
Chelsea's progress has stalled. They won the domestic Double the following the season, the first under Ancelotti, but their record in Europe has gone backwards – losing both legs of a last 16 tie with Internazionale, and losing both legs of their quarter-final against Manchester United last season.
That night in 2009 Hiddink proved he was the man to lead Chelsea's group of international superstars. It also gave the manager a taste for elite club management once more. And it left both parties with a sense of unfinished business.
The Hiddink effect
Guus Hiddink took over as caretaker manager at Stamford Bridge after Luiz Felipe Scolari's disastrous reign on 11 February 2009 with Chelsea fourth in the Premier League and in danger of missing out on Champions League qualification.
His first game in charge was a 1-0 victories at Aston Villa and a run of 11 wins from the last 13 Premier League games of the season saw Chelsea finish comfortably in third.
Meanwhile, Juventus were eased aside in the Champions League, Liverpool beaten in the quarter-finals after a pulsating 4-4 home draw, and only Andres Iniesta's last-minute goal stopped Chelsea knocking out Barcelona in the semi-final. Consolation came in the FA Cup, Frank Lampard scoring the winner as Everton were seen off 2-1 at Wembley.
Total record: P22, W16, D5, L1, F41, A20