Samuel Eto'o's and Jose Mourinho's considerable egos once saw them gelling like a cobra and a mongoose. An initial chat took place in the tunnel at a fevered Stamford Bridge.
"I know you are a great person and a great coach," the Barcelona striker told the Chelsea manager after a night of Champions League bile and bluster. "But in truth you are just a s---!" Now look at the pair. More love letters than insults have passed between them in the subsequent eight years and now, at the club that Mourinho revolutionised and that Eto'o once claimed was a disaster for world football, two of the game's more compelling personalities plan to work in perfect harmony again.
Asked why he had taken a 12 million pounds a year pay cut to join Chelsea, amid all the counter-offers he was receiving during Anzhi Makhachkala's extraordinary fire sale, the man on the biggest wages in football shrugged simply: "Because Chelsea has Jose Mourinho. And other clubs don't."
Now the international break is over and the big transfer window buys have begun to prepare for their weekend unveiling, none is more eye-catching than this second link-up between one of the finest strikers in the modern game and the man who used him so adroitly in winning a unique Italian/European treble at Inter Milan three years ago.
Whether Eto'o plays against Everton on Saturday is open to doubt after his injury in Cameroon's World Cup qualifier last weekend but Mourinho, after loaning Romelu Lukaku to Everton, has surely not brought such a high-maintenance luminary back to play a bit part. He is 32 but Eto'o - with 330 goals in 15 years - does not do bit parts. He does princely drama inimitably, though. He has flown in straight from a familiar furore, amid tales of rows with the Cameroon manager Volker Finke before the victory over Libya and, afterwards, threats to retire from international football "for family reasons".
Do not hold your breath. The volatile national hero has walked out before, only for the Cameroon Prime Minister to persuade him to return with a personal plea. The African play-off ties are in October and November and a month is a long time with Eto'o.
If Cameroon make it to Brazil, a large wager says the icon will be back for a fourth finals appearance. Eto'o is another special one; maybe Africa's finest footballer, a champion, a trailblazer, a defiant scourge of racism but Finke is not the only one ever to find him hard work.
This week, the Brazilian star Roberto Carlos claimed that, while at Anzhi, the Cameroonian, the most expensive of Anzhi's galactico signings with wages of approximately 350,000 pounds a week, had tried effectively to take over team management.
"It's quite confusing and odd when a footballer, instead of playing, is interested in bringing in players who are his friends," Carlos said. "He did everything at Anzhi, except play football. He wanted to control the club, taking my place and [coach] Guus Hiddink's." That would make Mourinho smile; he knows all about Eto'o's combustible tendencies from that tunnel confrontation in 2005 when the striker, after claiming he had been racially abused by a steward - a claim rejected and disproven - ranted about Mourinho being "shameless".
"Chelsea going through is a disaster for football," he told a Spanish paper. "If this team wins the Champions League, it would make you want to retire." Eto'o's other celebrated, but maybe apocryphal, soundbite was: "I'd rather sell groundnuts in my village than to play for a pathetic team like Chelsea."
The club's fans should find this easier to ignore than the old plastic flags taunt of Rafael Benitez because Eto'o's tongue always could lurch towards the uncontrollable, like the day at Barcelona when he screamed to the title-celebrating Nou Camp crowd: "Madrid, b------s! Salute the champions!" Mourinho could wind him up rotten. "Jose is inimitable," Eto'o noted. "As an opponent he can p--- you off, you can end up hating him. Yet if he's on your side, you know he's the best for how he motivates you."
A colleague likes to tell of how he once interviewed Eto'o in a Cairo hotel when the player was sitting naked in bed, propped up by a pillow and his modesty covered only by a duvet. The reporter felt he was like the teacher in The King and I. Mourinho, naturally, could recognise how a special one's ego would need massaging; hence the personal phone call to woo Eto'o to the San Siro. This is Mourinho's art with the biggest players. Even the precious Zlatan Ibrahimovic reflected on his Inter days this week: "You can argue with coaches but there is no question of that with Mourinho. From being a cat, he would make you feel like a lion. I was basically willing to die for him." Eto'o did the footballing equivalent.
This centre-forward supreme would do the donkey work on the flanks in a 4-3-3, or slot into a twin strike force in a 4-4-2 or even beaver away as a glorified wing-back as Jose convinced him of his worth as the consummate team player. Even if his signing was the fallback following the failed Wayne Rooney pursuit, that flexibility and selflessness makes him such an attractive proposition to Mourinho. He always admired Eto'o, even wanting him in his first reign at Chelsea only for Barcelona not to play ball.
Andrei Shevchenko came instead. The main question is whether, after two years of relative obscurity with his weird Anzhi existence of living in Moscow and only flying to Dagestan's armed conflict zone for home games, Eto'o is a yard slower, a goldmine healthier and a little less hungrier. Still, Mourinho is adamant he is just as motivated while his old sparring partner insists: "There is no other character like Jose. It is never boring when he's around." Likewise, it is never dull when Eto'o is in town. This could be fun.