BARCELONA, Spain (AP) --Lionel Messi netted his eighth brace of the season and created a third goal to steer Barcelona to a 3-1 win over a feisty Real Zaragoza on Saturday as the Spanish league leaders kept alive their club-record start.
Unbeaten Barcelona's 11th victory in 12 rounds maintained its eight-point lead over Real Madrid after the defending champions thrashed Athletic Bilbao 5-1 ahead of their critical Champions League trip to Manchester City.
Messi started the scoring at Camp Nou Stadium in the 16th. After Zaragoza leveled through Paco Montanes in the 24th, Messi assisted Alex Song four minutes later to re-establish Barcelona's advantage for good before adding a third goal in the 60th.
The Argentina forward's ninth multi-goal game in league play took his competition-best tally to 17 goals, five more than Madrid's Cristiano Ronaldo.
"Leo marks the difference because he's a special player,'' said Barcelona midfielder Andres Iniesta, who hit the woodwork 10 minutes from time.
"We are used to him doing what he does by now. We hope he keeps it up.''
Barcelona coach Tito Vilanova recovered Carles Puyol for his defense with the center back seeing his first action since dislocating his elbow on Oct. 2, while Song started as its holding midfielder in place of suspended Sergio Busquets.
After missing a clear chance early, Messi got the hosts going by slotting a left-footed shot just inside the post to finish off a move he started by playing Jordi Alba wide before sliding forward to receive the left back's return pass.
Zaragoza, which had won three of its previous four games, pushed forward in search of the equalizer that came from Montanes when he fired in a loose ball after a corner kick.
The visitors' elation lasted four minutes before Song scored his first goal for Barcelona since joining from Arsenal this offseason, slicing Messi's back pass through a crowded box to find the net.
Behind again, Zaragoza still succeeded in winning its share of possession and strung together attacks that tested Barcelona's defense before Messi decided the contest when he curled an unstoppable long-range strike off the lower part of the upright.
"There were stretches when Zaragoza made us chase them,'' said Iniesta. "They made us run and that wore us down, but I still think we played a well-rounded game.''
On Sunday, second-place Atletico Madrid visits Granada six points behind Barcelona.
Bilbao entered Santiago Bernabeu Stadium with the third-worst defense in the league, having allowed 21 goals, and only a strong performance by goalkeeper Gorka Iraizoz saved it from a historic rout.
Madrid jumped in front in the 16th when defender Jon Aurtenetxe scored an own goal when trying to stop Karim Benzema from shooting after the France striker latched onto Luka Modric's long pass from deep in his own half.
Sergio Ramos headed in Madrid's second goal at the half-hour mark off when Bilbao left him unmarked to meet Mesut Oezil's free kick.
Benzema, just back from injury, struck two minutes later, spinning inside the area and swerving a superb shot around Iraizoz before Bilbao midfielder Ibai Gomez pulled one back three minutes from halftime.
Benzema crossed for the wide-open Oezil to tap home in the 56th with Bilbao caught totally off-balance.
Substitute Sami Khedira also came back from injury in fine form for Madrid with a goal in the 72nd.
"We showed our desire to win and a serious attitude from minute one,'' said Ramos. "We now have a game in Manchester where we will play with practically our season on the line. As a football player, those are the kind of games you live for.''
Earlier, Roberto Soldado's 90th-minute penalty gave Valencia a 2-1 win over Espanyol, which finished with nine men and slid into last place.
Malaga was held to 0-0 at struggling Osasuna as the Costa del Sol side's winless streak reached four matches.
Valencia hosts Bayern Munich and Barcelona visits Spartak Moscow on Tuesday in the Champions League, while Malaga visits Zenit St. Petersburg and Madrid heads to northern England the next day.