Real Madrid goalkeeper Iker Casillas believes Barcelona are still the team to beat heading into the new Primera Division season.

Madrid have splashed out over 250million euros in under three months after returning president Florentino Perez promised a "spectacular sporting project" to try and get the club back amongst the elite of European football.

Cristiano Ronaldo was the biggest signing of the summer, and indeed of all time, after Madrid paid Manchester United a world-record £80million for his services, but he was not the Whites' only big-money addition with Kaka, Karim Benzema and Xabi Alonso also costing sizeable fees.

However, with eight additions to the Madrid squad this summer and around a dozen departures, it remains to be seen just how well, and how quickly, the new-look Madrid gel under former Villarreal coach Manuel Pellegrini.

In contrast, treble winners Barcelona have only added Zlatan Ibrahimovic and Maxwell to their all-conquering squad, and although Shakhtar Donetsk defender Dmytro Chygrynskiy is set to join within the next day or so, Pep Guardiola's side should be able to pick up where they left off last summer.

Casillas believes Barca are favourites to retain their title, but is confident his club have built a team capable of challenging their arch rivals on all fronts this season.

"They (Barca) are the champions of three competitions and they have a team that knows how to play," he said.

"We failed in the three competitions we played in last year and I want to get rid of that feeling. We want to play well and make the fans happy.

"The club has made a great effort to sign excellent players and we must all now do our best to win."

Madrid start their Primera Division campaign against the same opposition as they did last season, Deportivo La Coruna.

The capital club lost that match but it was played at Depor's Riazor home - a ground Madrid have not won at since the 1991/92 season - whereas this weekend's game will be played at the Bernabeu, where Madrid have won 32 of 39 league meetings between the two.

Barca, who last weekend completed a 5-1 aggregate win over Athletic Bilbao to add the Spanish Super Cup to their growing list of trophies under Guardiola, start their title defence at home to Sporting Gijon.

That match takes place on Monday night as Barca are in action in the European Super Cup against Shakhtar tomorrow night.

Last season, Guardiola's side took just one point from their opening two games against Numancia and Racing Santander - the club's worst start to a league campaign in 35 years - but they bounced back to become the first Spanish team to win the treble of league, cup and Champions League.

It is fairly certain that most interest will be focused on events at the Bernabeu and Nou Camp, but arguably the biggest match of the opening weekend takes place at the Mestalla where Valencia play host to Sevilla.

That game will pit two of the best attacks in La Liga against each other, with Valencia having so far managed to keep hold of their star trio of David Villa, David Silva and Juan Mata this summer, while Sevilla have added Alvaro Negredo to a strikeforce that already includes Luis Fabiano and Frederic Kanoute.

Both those sides will be hoping to fight for a Champions League berth at the end of the season, as will Atletico Madrid, who could be the biggest challengers to Barca and Madrid at the top of the table.

Like Valencia, Atletico have seemingly managed to ward off potential suitors for their star players Sergio Aguero and Diego Forlan, and having also reinforced their much-maligned defence, Abel Resino's men could be set for a good year.

Atletico winger Simao Sabrosa, whose side face Malaga first up, said: "We have a very strong team and we're going to fight to be in the top positions.

"You never know what can happen in La Liga. Our goal this season has to be to take a step up, reach third place in La Liga and play a good role in Champions League."

Elsewhere this weekend, promoted clubs Real Zaragoza and Tenerife face each other at La Romareda, while Segunda Division champions Xerez's first-ever top flight match is away to Real Mallorca.

In the other games, Espanyol, who have made Ivan De la Pena captain following the tragic recent death of Daniel Jarque, go to Athletic, Almeria are at home to Real Valladolid, Villarreal face Osasuna and Racing Santander host Getafe.