Messi converted from the spot 10 minutes before half-time and it was the Argentinian's cross that then forced Pau Torres into an own-goal, after an early double from the 17-year-old Ansu Fati had already put Barca in charge.

It meant Barcelona's past, present and future were all amongst the goals on the same afternoon as Luis Suarez, whose departure was confirmed on Thursday, marked his Atletico Madrid debut by scoring twice in a 6-1 win over Granada.

In a farewell message to his best friend and former neighbour last week, Messi took another swipe at the Barca board by saying he was not surprised by the clumsy way Suarez's exit had been handled.

His complaints raised doubts about his state of mind heading into the new season and at the end of a traumatic summer in which Barcelona's greatest ever player admitted he was being forced to stay against his will.

But Koeman insisted on Saturday that Messi had been "leading by example" in training and his confidence was repaid at Camp Nou, where the striker, and still club-captain, delivered an excellent display.

Messi's anger over Suarez shows he is still at odds with Barcelona's president Josep Maria Bartomeu and his long-term future remains uncertain, but on the pitch, for now at least, he seems ready to deliver.

Victories and goals could encourage him to stay, not to mention the incredibly talented Fati, who on this evidence can be a huge asset for his captain and his team's hopes of winning back the title.

Fati became Spain's youngest ever scorer earlier this month and the teenager, deployed on the left of the attacking trio, has now made an explosive start to the season for his club.

He fired Jordi Alba's pull-back into the top corner and then drove a second inside the post after Philippe Coutinho was allowed to carry the ball forward and spread it wide.

Fati then won the penalty, his feet too quick for Mario Gaspar, and Messi slid in his first goal of the season before his cross, aimed for Sergio Busquets, was poked into Villarreal's net by Pau.

Messi might have been watching on a few hours earlier as Suarez scored twice and set up another in a sensational 20-minute debut for Atletico.

Suarez laid on a goal two minutes after coming on as a substitute, his sumptuous pass finished off by Marcos Llorente, before scoring himself with a powerful header at the back post.

He then added another in injury-time, following up his own shot to make it six for a rampant Atletico at the Wanda Metropolitano.