Barcelona: Barcelona failed to capitalise on Real Madrid dropping points against Villarreal as the La Liga champions were held to a 1-1 draw at home to Atletico Madrid late on Wednesday, while talisman Lionel Messi limped off with a groin injury.

Ivan Rakitic nodded Barcelona ahead in the 41st minute, but the home side lost control after the break following an injury to midfield lynchpin Sergio Busquets while Angel Correa fired in the equaliser in the 61st, shortly after Messi had come off.

"Leo Messi has torn the groin muscle in his right leg. He will be out of action for approximately three weeks," Barcelona officials said in a statement.

If Messi's recovery goes according to plan, he will return to action for Barcelona against Deportivo La Coruna on October 15. "I'm not a doctor and I can't give any information here. But when Messi is injured, we all lose. Football loses," coach Luis Enrique said.

Messi was forced to miss eight weeks last season after injuring his knee, but Barcelona won eight of the 10 games they had to play without their star man. And Enrique said he was not worried about how his side would fare again without the maestro.

"Last year we also had an unfortunate situation, but the team kept playing at a high level," the coach added. "Without Messi, we are less stronger, but we can still be strong.

"We hope he improves and we're going to continue as we need to, playing with confidence."

Earlier on Wednesday, Real's 100 per cent start to the season came to an end as they drew 1-1 at home to Villarreal, which also halted their joint record run of 16 successive league wins. Real, though, remained at the top of the table on 13 points.

Sevilla are second on 11 points, Barcelona third on nine while Atletico are fourth with eight points.

Barcelona had plenty of possession in the first half but Atletico, who knocked them out of the Champions League last season, forced them into tight spaces and constricted their ability to create openings.

"We knew it wasn't going to be an easy game and we'd be attacking a team that would sit back and work hard.

"They gave us no space and made everything more complicated," Enrique said.

Messi was denied by Jan Oblak in one of few chances in a tight first half, but Rakitic broke free of Atletico's clutches to put Barcelona in front.

The champions did not kick on after the break, rocked by an exhausted Busquets being taken off and then Messi limping off.

A lapse of concentration from Barcelona defenders Javier Mascherano and Gerard Pique allowed Atletico substitute Correa to latch onto a through ball from Fernando Torres and fire in off the post.

Barcelona had 29 minutes to find a winner without Messi and despite chances for Pique and Neymar, Atletico held firm.

Earlier, Cristiano Ronaldo spurned two early chances in a lacklustre first half by Real, who allowed Villarreal opportunities at the other end.

Villareal captain Bruno Soriano gave his side the lead on the stroke of half-time with a boldly chipped penalty after Sergio Ramos had handled the ball in the area.

The Real captain made amends by equalising in the 48th minute.

"We were a much better side in the second half, but you can't always win every game in the last minute," said Real manager Zinedine Zidane.