Barcelona: Gareth Bale scored twice to help Real Madrid start the Spanish league with a 3-0 victory at Real Sociedad, while Atletico Madrid was held 1-1 after conceding a last-gasp goal to Alaves on Sunday.
Both title hopefuls from the capital outplayed their opponents. The difference was that Madrid proved more ruthless, and that was largely thanks to Bale.
Bale, who guided Wales to the semifinals of the European Championship in July, led a Madrid side that was on the road for its Liga opener without Cristiano Ronaldo and several other first-choice players.
His second-minute header set Madrid on its way to a comfortable win that youngster Marco Asensio put beyond doubt with his second goal in as many matches for the reigning European champions.
Bale wrapped up his brace by scoring in the closing seconds of the one-sided game at Anoeta Stadium.
"(Bale) began in the best way possible, by quickly scoring a goal," Madrid manager Zinedine Zidane said. "He has said that this season is important for him and he is showing it. We needed to begin the league well."
Barcelona also won its season-opener, a 6-2 rout of Real Betis on Saturday, but Atletico fell two points behind the powerhouses right out of the gates of what it hopes to make a three-way championship race for a fourth straight year.
Diego Simeone's side dominated Alaves, hitting the woodwork twice, and peppering the visitors' goalmouth with a barrage of shots that only increased as the match went on.
Kevin Gameiro appeared to have secured the win in his debut for Atletico after he converted a stoppage-time penalty, which was earned by Fernando Torres when he was fouled by Victor Laguardia.
But Alaves' Manu Garcia stunned Atletico with a long-distance strike seconds before the whistle in just his team's second venture forward.
"It leaves a sour taste in my mouth because we had it won," Simeone said. "But that's football. You win by scoring goals, and we couldn't convert."
Elsewhere, some of Sporting Gijon's fans marred its 2-1 win over Athletic Bilbao with racist chants aimed at Bilbao player Inaki Williams. The match's referee briefly stopped the match for the public announcer asked for the abusive chants to stop.
Madrid entered the Sociedad match without some of its key players, most importantly Ronaldo, who is recovering from an injury sustained in the Euro 2016 final. It was also without Karim Benzema, Pepe, Luka Modric and goalkeeper Keylor Navas.
But with Bale at his best, their absence went largely unnoticed.
Bale's bullet header to thump Dani Carvajal's pinpoint cross into the corner of the net appeared to demoralize Sociedad right from the start. It was his first goal of the new season after he was unfit to play the UEFA Super Cup against Sevilla last week.
Zidane started the 20-year-old Asensio over Colombia star James Rodriguez, who not long ago was considered among the club's top talents. Asensio proved the right choice when he scored five minutes before halftime.
Sociedad's slack defending left open a hole at the back that Asensio exploited with a run met by Raphael Varane's long pass. Asensio deftly controlled the lob before chipping goalie Geronimo Rulli, adding another classy goal to his superb strike that helped Madrid beat Sevilla in the season's curtain raiser.
Zidane, while saying that picking his starting 11 "makes my head ache," praised Asensio for what he called "his great match."
"(Asensio) is working well, he has quality, and talent," Zidane said. "He is good with the ball and is capable of breaking down the defense. His goal was incredible."
Zidane sent Rodriguez on as a substitute with the match well in hand to play the final quarter of an hour, but it is clear that he has to regain the starting role he enjoyed two seasons ago under former coach Carlo Ancelotti.
With Sociedad seeking a late goal, it was Bale who struck on the break, rounding Rulli and steering the ball into an empty net.
Sociedad honored former player Dalian Atkinson with a round of applause early in the match. Atkinson died after being shot with a stun gun by British police earlier this week.