Eibar are enjoying an excellent campaign in their first season in Spain's top flight, sitting eighth in the table after 20 matches.
A small town with a population of under 30,000, Eibar's tiny Ipurua Municipal Stadium is a reminder of just how far the club has come in recent years.
Founded in 1940, Eibar's ground holds just over 5,000 fans but those in attendance this season have seen a side fight excellently against the odds.
European champions Real Madrid have already come to town - they won 4-0 in November - but the visit of Atletico is sure to have the locals licking their lips.
"We will try to use our weapons and be strong," Capa told Eibar's official website.
"On Saturday we have a battle and we'll go for it.
"[Atletico's team] is very similar to ours, very intense and strong in strategy.
"[They play] with intensity and [do] not relax at any time."
The Spanish champions will visit Eibar battered and bruised, too, after a fiery Copa del Rey quarter-final second leg on Wednesday.
Atletico, who trailed 1-0 after a first-leg loss at Barcelona, suffered a 3-2 home defeat - giving Barca a two-goal success over the two legs.
Atleti finished the game with nine men after captain Gabi was sent off during the half-time break and Mario Suarez was given his marching orders late on.
It could have been worse, too, if Arda Turan had been punished for throwing one of his boots in the direction of an assistant referee.
Atletico now revert their attention to league matters, where they are four points adrift of leaders and city rivals Real Madrid.
The physical and mental exertions of their cup defeat might just play a part in Eibar, but the hosts will have to keep out Fernando Torres.
Having returned to boyhood club Atletico on loan from Milan, Torres has scored against Real Madrid and Barcelona in the last month.
Eibar have scored just 24 league goals this season - four fewer than Real Madrid's Cristiano Ronaldo - with Mikel Arruabarrena their top scorer.
Arruabarrena has netted five Liga strikes this term and was a member of Eibar's squad in both the second and third tier.
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