At the beginning of the Ligue 1 season in France, the overwhelming opinion among the country's pundits was that the most compelling duel would not be the one for the top of the table, but the joust between the men who play up top in the same Paris Saint-Germain team. The title tussle between Lyon, Marseille, and PSG has been tighter than predicted. But not so much as to distract entirely from the Ibra and Edi show.
The thought process is that Zlatan 'Ibra' Ibrahimovic, the PSG captain and totem, and Edinson 'Edi' Cavani, carrier of the highest price-tag of any footballer to ever come to France, have a complicated relationship.
Signs of its complexities are forensically sought in every game, and Laurent Blanc, the PSG coach, teases the media about what he sees as its obsession, the focus of questions: How often do Ibrahimovic and Cavani pass to another? Are they making complementary runs? Or treading on each other's toes?
Beyond the tactics board, there's a theory the pair are, behind closed doors, engaged in a sort of Bois-du-Boulogne Big Brother series, that will end with an exit - mostly likely Cavani's - at the end of the season. There's attention to how enthusiastically they rejoice in one another's goals. Even L'Equipe, the sports newspaper that keeps most of its speculations fairly sober, noted the last time an Ibrahimovic pass set up a Cavani goal, against Evian in January, "the Uruguayan celebrated on his own, before being joined by most of his team-mates, though certainly not Ibrahimovic.
He returned to the middle of the pitch at a slow pace and with an air of being utterly unconcerned with the delight of his colleagues." Cavani then gave Ibrahimovic a light pat on the back as a thank-you."
Perhaps that's because they were in 89th minute, and the captain felt tired. Maybe it was because the goal was PSG's fourth in a 4-2 win, and the contest had already been won. Or perhaps Ibrahimovic, as skipper, had a point of authority to make. Cavani lost some popularity with PSG supporters at the turn of the year by returning late from his winter holiday in South America, missing a portion of a training camp.
But the main source of the perceived froideur between Cavani, 28, and Ibrahimovic, 33, is an interview Cavani gave to L'Equipe at the same crossroads moment of last season that PSG find themselves at today. He spoke to the paper just ahead of the Champions League quarter-final against Chelsea.
He had something on his chest. Cavani spoke candidly about the frustrations of his first seven months since joining PSG from Napoli for euros 64m. He explained how he felt his position in PSG's preferred 4-3-3 did not do justice to his best assets. Blanc tends to assign Cavani to the wider attacking positions. Zlatan, not Cavani, owns the centre-forward berth, from where the Swede is encouraged to drop deep.
After a while, Cavani complained, the situation "can become a burden." Eleven months later, PSG still use Ibrahimovic in a broadly similar way, Cavani to his right. And Blanc's formula mostly works. It yielded a Ligue 1 title for PSG in 2014 and 26 league goals for Ibrahimovic, 10 more than Cavani.
The story this season has been slightly different.
Ibrahimovic missed a period of the autumn with injury, so Cavani spent more time in an orthodox number nine's territory. If he hardly seized his moment with a flurry of goals domestically, in Europe he has been prolific: 10 of PSG's points in a group phase in which they made heavy weather of matches against Apoel and Ajax were directly gained by the Uruguayan's goals. They come to London on equal terms thanks to Cavani's goal in the 1-1 draw in the first leg, his seventh in as many Champions League games.
Already he has made a better impact on Chelsea than he did last year, when he followed up that forthright interview with some unusually flimsy finishing.
Cavani's equaliser against Chelsea last month was a header. His aerial threat might be one area where he stands strong comparison with Ibrahimovic, who ticks many more boxes for what he can offer outside the penalty area. Off the pitch, it is easy to gain the impression Ibra and Edi are chalk and cheese.
Through Ibrahimovic's autobiography, 'I am Zlatan', with its stories of a rascal youth and a non-conformist adulthood, you quickly get used to a high ratio of profanities-per-page.
Turn to Cavani's 'Vita, Calcio e Fede' - 'Life, Football and Faith' - and there's a parable in almost every paragraph. Cavani's Christian faith has evidently been a defining part of his life.
They do have one hobby in common. They hunt, and can handle a rifle. Ibrahimovic roams in his free time over the tundra landscapes of Swedish islands, pursuing moose. Cavani stalks the fauna of the plains and lakelands of his native Salto region in Uruguay. They may or may not not exchange tales in the dressing-room of their adventures with wildlife. It would surprise Parisians greatly if they ever set off on a tandem safari holiday together.