BARCELONA, Spain (AP) -- Runaway Spanish leader Barcelona travels to fourth-place Malaga on Sunday to enter its toughest period of the season with five of its next eight games away from the Camp Nou.
Lionel Messi, fresh from collecting his record fourth world player of the year award, will lead Barcelona with his league-best 27 goals. Barcelona is aiming to reach the season's midway point unbeaten after winning 17 games and drawing just once.
Barcelona and Malaga will then meet twice more over the next two weeks in the Copa del Rey quarterfinals.
"These three games against Malaga will be difficult," said Barcelona goalkeeper Jose Pinto, who handles the Copa games while Victor Valdes plays in the league. "We will have to see how the two teams handle the mental wear and tear, which above anything else will be determined by the results."
Atletico Madrid is 11 points behind Barcelona and hosts Real Zaragoza on Sunday.
Real Madrid - 16 points off Barcelona's pace in third - will try to avoid another slip at last-place Osasuna on Saturday without the suspended Cristiano Ronaldo and its defense in tatters.
While Barcelona shows no signs of slowing down, its stumbling chasers' last hope of catching the Catalan club resides in the bumpy road the coming weeks offer.
After the game at Malaga, Barcelona has subsequent trips to in-form Real Sociedad, Valencia, Granada and archrival Madrid. It will also pursue its Copa defense and start the Champions League knockout rounds against Italian side AC Milan.
Barcelona will face its packed calendar with coach Tito Vilanova and assistant Jordi Roura sharing coaching duties while Vilanova continues chemotherapy and radiotherapy after his recent surgery to remove a tumor from his throat.
Vilanova, who has led Barcelona to a league record start in his first season since taking over from Pep Guardiola, will not be on the touchline for Sunday's game. He has reportedly gone to New York to continue his treatment on a second tumor in two years, according to the Spanish press.
"Just because Tito isn't physically with us doesn't mean that our philosophy will change," Pinto said. "He will be present in his way."
Messi will most certainly be back in Barcelona's starting lineup after sitting out Thursday's 5-0 win over second-tier club Cordoba as it eased into the next round of the Copa del Rey. David Villa and Alexis Sanchez both took the rare opportunity to star by scoring two goals apiece with Messi watching from the bench.
Malaga has won three straight league games at La Rosaleda Stadium, and Manuel Pellegrini's team boasts the league's stingiest defense with only 13 goals conceded through 18 games.
Malaga needs the three points to ensure it holds on to fourth place and Spain's last Champions League spot. Real Betis and Levante, which play earlier on Sunday, can both move ahead of Malaga if it falters.
"We can't play defensively. We have to go out to win," said Malaga forward Javier Saviola, who played for Barcelona as a teenager. "It will be a special game for me because (Barcelona) treated me well."
Madrid will be without Ronaldo and his team-best 16 goals after he earned a one-game suspension for picking up his fifth yellow card last round.
Nor will its defense be in good shape with Sergio Ramos beginning a five-game ban for insulting the referee in the Copa del Rey. Fellow center back Pepe is also out recovering from surgery on his ankle.
The debate coach Jose Mourinho has provoked over who should start in Madrid's goal will have to wait another week. Regular starter Iker Casillas will be back between the posts while Adan Garrido serves a one-game ban after seeing a red card last round.
"Let's be realistic, (defending the league title) will be difficult, but we have to keep fighting," said Madrid forward Gonzalo Higuain, who recently returned from injury. "We want to recover our form from last season and become the team we once were."
Osasuna could receive a boost from new midfielder Miguel de las Cuevas, the former Atletico Madrid player just arrived on loan from second-division Sporting Gijon.
The round starts on Friday with Rayo Vallecano seeking a fourth straight win at Athletic Bilbao.
Also Saturday, it's: Valencia vs. Sevilla; Valladolid vs. Mallorca; and Espanyol vs. Celta Vigo. Sociedad hosts Deportivo La Coruna on Sunday, and Granada visits Getafe on Monday.