Atletico Madrid is on the cusp of reaching the semifinals of Europe's top-tier competition for the first time in 40 years as it welcomes Barcelona FC to its Vicente Calderon Stadium on Wednesday for the return leg of their Champions League quarterfinal.
Atletico holds a narrow advantage after scoring an away goal in the 1-1 first leg result at the Camp Nou, and can expect raucous support from a fan base that has tasted much success in the Europa League of late, but has not reached the final four among Europe's elite since 1974.
Atletico is clinging to the hope that striker Diego Costa will overcome a hamstring injury picked up in the first leg, while playmaker Arda Turan is also on the mend.
Barcelona is vying to reach the semifinals of the Europe's top-tier competition for the seventh straight season.
Here are five things to know about Wednesday's matchup between the Spanish league rivals:
COME ON COSTA
Atletico Madrid striker Diego Costa has been quite possibly the key to Atletico's improbable season, which sees it sitting top of the Spanish league - one point ahead of Barcelona - with just six games to play. But the Spain striker's availability could prove crucial to advancing deeper into the competition for the first time since 1974. Midfielder Arda Turan could return after also missing Saturday's 1-0 win over Villarreal.
Atletico coach Diego Simeone said Tuesday that Costa would only play if 100 percent, even suggesting little-used Adrian Lopez could start in attack despite the return of Raul Garcia from a ban.
''Costa is to us what Cristiano (Ronaldo) is to Madrid or (Lionel) Messi to Barcelona. But I don't know what percent he's at for a return,'' Simeone said before the final training which could determine Costa's participation. ''A player is only useful if he's a minimum 90 percent (fit). A player who is 50 percent is of no use to us.''
Barcelona midfielder Xavi Hernandez wants his team to score quickly and place the pressure on Atletico.
''Then we can see how they react,'' Xavi said.
Atletico, alongside Real Madrid, is the only unbeaten team left in the competition.
Lionel Messi, who has scored 20 career goals against Atletico, may be the best option but has yet to break through and beat Thibaut Courtois in four meetings this season as Atletico's league-best defense has been the most effective team in a