Chelsea vs Arsenal preview: The Brazilian Betrayer and the avenging Gabriel

Fancy a clattering, Costa? Good.

There is a traitor in our midst, someone who will switch allegiances at the merest whiff of lucre or silverware. At first glance, one might think that we're again autopsying Fàbregas’ flight. I'm done flogging that little horse, however. For what it's worth, Fàbregas's betrayal was not in going to Stamford Bridge; it was in fleeing the Emirates. He's just another Nasri or van Persie in my eyes.

Instead, there's another, deeper betrayal on my mind: that of Diego Costa. It's one thing to switch when a club starts talking about weekly wages; it's quite another when a country starts beckoning with the "come hither" gazes. Diego Costa, né Diego da Silva Costa, formerly known in the Brazilian way as simply Diego, was once one of Brazil's finest. However, the Beast of Brazil bolted for Spain. Something in me wonders if our own Brazilian might have something to say about that.

Costa made his switch from Brazil to Spain in 2013 – ahead of the 2014 World Cup, hosted by Brazil. That's right, in a country perhaps as mad about o jogo bonito as any on the planet, Costa fled, perhaps sensing the grass would be greener in Spain than it ever could be in Brazil. Why not? Brazil's squad is rife with attacking options. The Seleção can deploy Neymar and Hulk, and who can compete with them? Apparently, not Costa.

Rather than represent the country of his birth when it would host the world's biggest sporting event, he jilted Brazil, apparently believing that Spain, despite boasting of plenty of forwards, offered him a better chance at playing time – or, at least, glory. Spain has had on its roster Fernando Torres, Fernando Llorente, David Villa, and Alvaro Negredo, but Vicente del Bosque didn't seem to trust any of them. A squad heavily favoured to win the World Cup but in need of a striker? I'm not sure that I'm only describing Spain here, but Costa did. For Spain to fail to advance from the group stage while Brazil made it to the semi-final delivers just a bit of poetic justice.

Turning his back on his entire country for an easier route to glory, however, seems to fit nicely with Mourinho's mentality, and so it's no surprise that Costa found his way to Chelsea. All the loyalty in those two you could fit inside a thimble.

Ahead of Sunday's clash, we now have someone who might have something to say about Costa's decision. Clearly, Costa is not the only Brazilian in Chelsea's squad, so we can't make too much of it. I'm sure Willian, Oscar, and Ramires have come to peace with their erstwhile countryman's fungible loyalties, perhaps reasoning that winning the EPL justifies it.

When we went to Stamford Bridge, we didn't yet have our own Brazilian in the fold, though, and that Brazilian might have something more to say about the situation, if only on the pitch: Gabriel Paulista. It's only since joining Arsenal that Gabriel was called up for Brazil for the first time – the surge in patriotic pride he must feel stands in stark contrast to the mercenary cynicism that Costa brazenly showed.

Add to that the tension, friction, and hatred between Chelsea and Arsenal, and we could have a feisty little melee between the combative forward and the fearless defender. They have clashed before, back when both were in La Liga, and Gabriel did what he could to keep Costa from scoring in a 1-1 draw in 2013, clattering him at one point along the way (above). The two will frequently find themselves grappling in the trenches, and if Gabriel can get under his skin, the volatile Costa could find himself getting sent off.

I wonder whether Gabriel can push a few buttons related to patriotism and loyalty? Even if Chelsea do sit back and dare Arsenal to pick the lock, Costa will surely venture forward in search of the solitary goal Mourinho craves. When he does, he will have to cope with the grit of Gabriel, whose speed and physicality belie his positional sense and timing. He's just as capable of denying service to Costa as he is of dispossessing Costa when he does have the ball at his feet.

No Chelsea-Arsenal clash is short on subplots, but with all of the attention on Fàbregas's return to the Emirates, it would be remiss of us to overlook the one between the two Brazilians – er, our Brazilian and their betrayer.