Luis Suarez partnered Diego Costa for the first time and scored as Atletico Madrid beat struggling Celta Vigo 2-0 in La Liga on Saturday.
Luis Suarez left Barcelona for Atletico Madrid, after the arrival of Ronald Koeman.
Lionel Messi has been in open conflict with his club but it had no detrimental effect on his form as his 13th minute penalty was the difference in a tight encounter.
An investigation was opened into possible fraud concerning an Italian exam taken by former Juventus transfer target Luis Suarez.
Luis Suarez, who hit 198 goals for Barcelona, becoming the third highest goalscorer in the history of the club, cried as he bid an impromptu farewell to the club on Thursday.
Atletico Madrid announced the signing of Barcelona forward Luis Suarez late on Wednesday, confirming the Uruguayan striker is set to continue playing in La Liga rather than joining Juventus in Italy.
Juventus are looking for a replacement for Argentinian Gonzalo Higuain who has left for David Beckham's MLS side Inter Miami.
Thomas Mueller and Philippe Coutinho both scored twice as Bayern Munich blew Barcelona away in a merciless display that will prompt serious questions over Lionel Messi's future in Spain.
Barcelona and Espanyol were both reduced to 10 men in the second half before Luis Suarez netted the winner for the home side at the Camp Nou.
Antoine Griezmann returned to Barcelona's starting line-up at La Ceramica and repaid the faith with a stunning goal, teed up by Lionel Messi.
Luis Suarez twice put Barcelona in front at Balaidos with his first goals since January but Iago Aspas bent in a late free-kick to earn Celta Vigo a draw.
Liverpool won the Premier League title after a span of 30 years as Chelsea defeated Manchester City 2-1 on Thursday.
Victory extends Barca's advantage at the top of La Liga to five points over Real Madrid, who can reduce the gap back to two when they restart at home to Eibar on Sunday.
Eden Hazard was looking beyond Real Madrid to the Euros after undergoing surgery on his right foot in March while some felt Luis Suarez had played his last game for Barcelona after having a knee operation in January.
Lionel Messi has been suffering from tightness in his right thigh and had not trained fully since last Tuesday.
Lionel Messi trained alone on Saturday at Camp Nou after sitting out the team's previous two sessions, raising doubts over his involvement in the trip to Mallorca.
Luis Suarez was injured for four months and is expected to return to action on June 13, when Barcelona take on Mallorca.