BARCELONA, Spain (AP) After a quiet summer for the Spanish league marked by famous farewells instead of lavish outlays, two coaches could take center stage as Barcelona opens its title defense this weekend with Real Madrid again the main challenger.

Luis Enrique led Barcelona to a rare sweep of the league, Champions League and Copa del Rey titles last season in his first season in charge, but his ability to motivate the team is now being questioned after Athletic Bilbao dealt the team a 5-1 aggregate loss in the Spanish Super Cup.

Barcelona will get a chance to avenge that humbling result come Sunday when it starts the Spanish league season at San Mames Stadium.

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''It will be a tightly contested league, but we have to be optimistic,'' said Luis Enrique. ''I see my team as convinced. We want to keep giving our fans reasons to celebrate and to continue being the team the world admires.''

Moments after the match at San Mames finishes, Rafa Benitez will make his competitive debut as Madrid's new manager at promoted club Sporting Gijon. Benitez inherits a star-studded squad led by Cristiano Ronaldo, but the team displayed a bewildering inability to win big matches as it faltered across all competitions last season.

Madrid club president Florentino Perez is yet to make a big splash in the transfer market, instead limiting himself to buying players like Mateo Kovacic and Kiko Casilla to help, not transform, his team.

But even if Madrid managed to pry goalkeeper David de Gea away from Manchester United before the end of August, this summer will be remembered for the departures of Barcelona's Xavi Hernandez and Madrid's Iker Casillas, who combined for seven Champions League titles and 13 league crowns in addition to leading Spain in its 2010 World Cup victory.

The exit of the aging pair of friends marks the end of an era and has left voids at the fierce rivals.

With Lionel Messi providing the goals, Andres Iniesta will have to fill Xavi's more vocal leadership role. Madrid, however, is entering the season with questions regarding leadership and whether feeding Ronaldo's insatiable appetite for scoring is the way to topple Barcelona.

One Spanish league title in seven years is a paltry showing for the richest sports club in the world, and Perez is again under pressure to turn his big payroll into an equally big payoff.

Benitez began his coaching career in Madrid's youth academy before making his mark at Valencia and Liverpool, and he knows there is no place in the capital for losers.

''The president and I both know that being No. 1 is the only thing that matters, and being second isn't worth anything,'' Benitez said after stifling tears at his presentation in June. ''I have to adapt as quickly as possible because this is the demand from the very first day.''

Atletico Madrid, the surprise 2014 champion, has been the biggest mover in the summer market. Coach Diego Simeone has a formidable attacking unit after the club bought Colombia striker Jackson Martinez from FC Porto and Luciano Vietto from Villarreal to go with Antoine Griezmann and Fernando Torres. Midfielder Oliver Torres returns from his one-year loan to Porto to hopefully make up for Arda Turan's exit to Barcelona.

Despite the injection of talent up front, Atletico would need to rekindle its perfect run from two years ago to challenge the top two teams.

Valencia and Sevilla are again set to fight for a top-four finish, with both also rounding out Spain's five-team contingent in the Champions League. Nuno Santo Espirito is back for a second season in charge of Valencia, which has reinforced its squad with young striker Santi Mina.

Still, the financial inequality in the league is clearly seen by glancing at the offseason operations conducted by lower and mid-tier teams.

Celta and Malaga sold their best players, while indebted clubs such as Espanyol, Deportivo La Coruna, Getafe and Rayo Vallecano have mostly patched together squads through loan deals and free arrivals.

Along with Sporting, Las Palmas of the Canary Islands and Real Betis are the newcomers to the top flight and. The season kicks off Friday when Malaga hosts Sevilla.