European preview: Holders Juventus begin Serie A challenge
A Juventus side strengthened by the signing of Argentina forward Carlos Tevez begin their bid for a third successive league title when the Italian Serie A gets under way on Saturday.
Antonio Conte's side eased to the championship last season, finishing nine points ahead of nearest challengers Napoli.
They begin 2013-14 at Sampdoria and sent a warning to their rivals last weekend with a dominant 4-0 win against Lazio in the Super Cup.
Tevez, a summer signing from Manchester City, made his debut in that game, scoring Juventus's fourth goal.
Conte also increased his attacking options over the summer with the signing of Spain forward Fernando Llorente from Athletic Bilbao, while keeping together the core of the side that has dominated Italian football for the past two years.
Last season's runners-up Napoli now have former Chelsea boss Rafael Benitez in charge.
They begin against Bologna on Sunday without the firepower of Uruguay forward Edinson Cavani, who joined Paris St-Germain in the summer.
AC Milan, champions in 2011, will also have their eye on a title challenge. However, they are without 10 players for Saturday's opener against Hellas Verona - including midfielders Kevin-Prince Boateng and Nigel De Jong.
In other games, Inter Milan host Genoa on Sunday while Fiorentina - strengthened by the signing of Germany striker Mario Gomez from Bayern Munich - face Catania on Monday.
Barcelona travel to Malaga on Sunday with the availability of reigning World Player of the Year Lionel Messi in doubt.
The Argentine - who scored twice in La Liga champions' 7-0 opening-round rout of Levante - suffered a bruised thigh in the 1-1 draw with Atletico Madrid in the first leg of the Spanish Super Cup on Wednesday.
Rivals Real Madrid could have announced the world record-breaking arrival of forward Gareth Bale from Tottenham before they travel to Granada on Monday. Head coach Carlo Ancelotti will be hoping for a more routine victory than the hard-fought triumph secured by a late Isco goal last weekend against Real Betis.
Elsewhere, the Giovani dos Santos-inspired Villarreal will hope to continue their winning return to the top flight when they host Valladolid on Saturday.
Saturday marks the 50th year of the Bundesliga and Bayern Munich will look to celebrate the occasion by breaking a club-record run of 27 league games without defeat when they host Nurnberg.
Pep Guardiola's men have recorded wins in their first two games of the season and they have no new injury concerns as they bid to make it three wins from three.
Attacking midfielder Mario Gotze, a summer signing from Borussia Dortmund, could come into the side after recovering from a long-term injury while midfielder Thiago and winger Franck Ribery are also available.
"A derby is special. Nurnberg are always extremely aggressive against Bayern," said Guardiola.
Bayer Leverkusen have also picked up maximum points so far this season and they will look to continue their excellent start when they host Borussia Monchengladbach on Saturday.
Robert Lewandowski scored his second goal of the season as Borussia Dortmund made it three wins from three with a 1-0 win against Werder Bremen on Friday.
Laurent Blanc goes in search of his first Ligue 1 win as Paris St-Germain head coach when he takes the big-spending outfit to play Nantes on Sunday.
Table-toppers Lyon have been victorious in their first two top-flight fixtures, but will hope to recover from their midweek 2-0 Champions League qualifying humbling at the hands of Real Sociedad when they host Stade Reims.
On Saturday, Guingamp host Lorient in the Brittany derby and Marseille play Valenciennes.
Monaco, meanwhile, played out a goalless draw with Toulouse on Friday in a game that was played behind closed doors.
PSV Eindhoven, top of theEredivisie on goal difference, travel to winless Heracles on Saturday while second place FC Zwolle host Cambuur.
Struggling Feyenoord are at home to NAC Breda on Sunday looking to pick up their first points of the season, while Vitesse take on Twente.
Ajax dropped points for the first time this season as they played out an entertaining 3-3 draw with Heerenveen on Friday.
Reigning champions Porto play their first home game of the season on Sunday when they host Maritimo, while Benfica face Gil Vicente hoping to collect their first points of the season.