Diego Costa Spoils Gareth Bale Debut: Is Atletico, Not Real Madrid, Barcelona's Primary Rival?

Gareth Bale may have gotten his dream move away from Tottenham Hotspur, but his first game at the Santiago Bernabeu Stadium was something approaching a nightmare. Atletico Madrid had not won a match at the Bernabeu this century before winning at the end of last season. Now, they've made it two in a row.

Diego Costa ran onto a slipped pass from Koke, putting Los Colchoneros up 1-0 early. That was enough, as the uber-disciplined Atleti dominated most of the game.

Both Atleti and Barca are a perfect 7-for-7; Barcelona are first by virtue of goal difference, but they are tied on points with Atletico.

Costa and Lionel Messi are tied atop the La Liga scoring charts with 8 goals (though Messi has played only 450 minutes compared to Costa's 601.) In addition, Koke is tied with Cesc Fabregas atop the assist chart (Koke has played a bit more.) Goalkeepers Thibaut Courtois and Victor Valdes are both tied with Granada's Roberto for the best goals-against-average.

Their two encounters so far this season have been draws, Barca securing the Supercopa by virtue of the away goals rule.

Real Madrid have come out just a bit shaky from the gate again. They struggled to control the game against Villarreal and dropped points against the Yellow Submarine. Against Elche, they needed a very late, very dubious penalty to win. And of course, they have just endured their first loss of the season.

(Atletico and Barcelona have had their near-misses, too, and they have benefited from a call here and there. Yet, they remain perfect.)

With all this in mind, is Atletico the #1 threat for the league leaders?

They have a strong team, tough and streetwise - just like their coach, Diego Simeone. Simeone has revitalized Atleti from a team that self-identified as "cursed" to a squad brimming with confidence and winner's medals.

They lost arguably their best player, Radamel Falcao, in the off-season, but they strengthened in other aspects. Leo Baptistao and David Villa were brought in as replacements, and Diego Costa has improved. Toby Alderweireld was signed to add more depth to the defense.

The key question is: can Atletico maintain their impressive form as the toil of the Champions League campaign settles in? They have a bit more depth than last year, but a relatively thin squad (compared to the big two) may be their undoing.

And on the other hand, Real Madrid should logically improve. Gareth Bale is just beginning to settle in. Los Blancos are still figuring themselves out in the Carlo Ancelotti era. They are having trouble controlling matches and penetrating ironclad defenses without their best midfielder this past season, Mesut Ozil, who now resides in London.

Last year, Atletico began strong and Real weak. By the end of the season, Real finished second, Atleti third. Maybe Los Colchoneros can maintain their form this year.

In either case, Barcelona have two teams in Madrid to watch out for.