Barca dominated possession and Luis Suarez had several early chances but it was Villarreal who took the lead with Denis Cheryshev redirecting a Mario Gaspar shot past keeper Claudio Bravo on the half hour.
The Bavarians have now won the German league title a record 29 times.
A summary of Sunday's action in Serie A and Bundesliga.
Arsenal led a list of nine clubs who grabbed a second win in as many games in the Europa League group phase as France striker Olivier Giroud scored his 100th goal for the club in a 4-2 win at BATE Borisov on Thursday.
Belgium have retained injured Vincent Kompany in their final World Cup squad but put fellow defender Laurent Ciman on standby in case the Manchester City skipper is not fit for their opening match in Russia.
Red Star, who won the European Cup in 1991 and reached the latter stages the following season, finished second in Group H behind Arsenal who crushed BATE Borisov 6-0.
European champions Bayern Munich led the charge into the last 16 of the Champions League when they beat Viktoria Plzen 1-0 to chalk up a record-equalling ninth straight victory in the competition on Tuesday.
Photographic summary of the football matches played across Spain, Italy and France
IMAGES from the English Premier League matches played on Saturday.
Barcelona's talismanic Lionel Messi remains the driving force of a talented side on the brink of repeating 2009's historic treble despite a change in their coach and style of football, not to mention a host of players.
Images from the football matches played across Europe on Sunday
Barcelona coach Luis Enrique is head strong but it appears as though he may be fighting a losing battle with the four times World Player of the Year.
Lionel Messi was at the top of his game as Barcelona earned a 3-2 win at Athletic Bilbao on Wednesday to move up to third in La Liga.
IMAGES from football matches played in the Spain, Germany and Portugal on Wednesday.
Lopetegui blends youth and experience in Spain World Cup squad
Zlatan Ibrahimovic and Cristiano Ronaldo come face-to-face next month when Sweden meet Portugal in a World Cup playoff and they sharpened their claws with six goals between them on a thrilling night of Champions League action on Wednesday.
A round-up of Saturday's action in La Liga, Ligue 1 and Serie A.
US Open champions Marin Cilic and Serena Williams kicked off their China Open campaigns with straight sets victories against battling underdogs on Monday, but Rafael Nadal suffered defeat in a rare doubles outing on his return from injury.
News of all that's transpired on and off the football field
News of all that's transpired on and off the football field
Diego Costa continued his rich vein of form as he helped leaders Chelsea to a 3-0 win over Aston Villa while Louis van Gaal enjoyed only his second Premier League win as Manchester United manager following a 2-1 victory against West Ham.
Paris St Germain's Zlatan Ibrahimovic scored his first Ligue 1 goal this season before missing a penalty as they beat En Avant Guingamp 3-0 to extend their lead to four points on Tuesday.
Lionel Messi dragged a nervous Barcelona to a 1-0 win at home to Levante in La Liga, while Cristiano Ronaldo converted two late penalties on his 100th appearance for Juventus in all competitions as the Serie A titleholders ground out a 3-1 win away to a dogged Genoa side.
Atletico Madrid demonstrated their remarkable team spirit to come roaring back from two goals and a man down to draw 2-2 at Liga debutants Girona on Saturday, after Antoine Griezmann had been sent off for the first time in his career.
News of all that's transpired on and off the football field.
News of all that's transpired on and off the football field
News of all that's transpired on and off the football field
News of all that's transpired on and off the football field
Images from the soccer matches played across Europe on Saturday.
News of all that's transpired on and off the football field
IMAGES from the 2020 Euro Qualifiers played on Monday
Atletico Madrid got their La Liga campaign up and running in less than convincing fashion when Antoine Griezmann's deflected free kick secured an edgy 1-0 win at home to promoted Las Palmas on Saturday.
News of all that's transpired on and off the football field
The victory saw the unfashionable Madrid club tighten their grip on the coveted fourth spot in the table by moving on to 58 points after 36 games, three points clear of nearest challengers Sevilla, who lost to Leganes on Friday.
Summary of World Cup qualifiers played across the world on Thursday
Lionel Messi's penalty earned Argentina a 2-1 win over Croatia after a fortunate equaliser that stood despite an unintentional handball by Sergio Aguero in a friendly at West Ham United's Upton Park ground on Wednesday.
As Manchester United prepare to embark on a new era following Louis van Gaal;s departure, Bikash Mohapatra/Rediff.com offers a diagnosis of what went wrong with the most successful Premier League club after Sir Alex Ferguson called it a day.
Images from the 2018 World Cup qualifiers played in Europe on Monday
News of all that's transpired on and off the football field
News of all that's transpired on and off the football field