BARCELONA (Reuters) -LaLiga leaders Barcelona lost 1-0 to Leganes on Sunday with defender Sergio Gonzalez's early header enough to stun the wasteful hosts who lost their second consecutive league game in front of their own fans.

While they have been excellent in the Champions League with five wins in six games, Barcelona have struggled in LaLiga for over a month, with only one victory in their last six league matches.

Barca remain top of the LaLiga standings with 38 points, level with Atletico Madrid - who they host on Saturday - and one point ahead Real Madrid in third, with both their title rivals having a game in hand.

It was Leganes's first ever win at Barcelona and left them 15th in the table on 18 points.

Leganes took the lead from a corner after four minutes when visiting captain Gonzalez rose unmarked at the near post to fire an unstoppable header past goalkeeper Inaki Pena.

Barca immediately went after the equaliser but, despite dominating proceedings throughout the match with over 80% possession, they were clueless as they sought to overcome a disciplined and well organised five-man Leganes defence, spurning a handful of opportunities.

They failed to hit the target with 16 of their 20 shots in the game and when they did, they hit a wall in Leganes goalkeeper Marko Dmitrovic who made three spectacular saves in the first half.

The 32-year-old Serbian keeper made a brilliant reflex save to deny a first-time effort from Robert Lewandowski in the 10th minute after fine individual play by Raphinha down the left.

Then, he worked his magic with a stunning save in the 33rd minute to palm a Raphinha volley against the crossbar and stepped up again a few minutes later to block a Lewandowski effort when the striker was one-on-one.

The hosts' frustration grew after the break and they missed several chances with Dani Olmo, Lamine Yamal and Raphinha all wasting good opportunities while Lewandowski and Jules Kounde missed sitters from close range.

"It's impossible for us to go home feeling happy after what happened today," a visibly frustrated Pedri told DAZN.

"We didn't have the spark that is needed up-front to score goals and we have to go into games better, we can't allow our rivals to score goals in the beginning like this.

"I think we had created chances but we have to know how to finish. It's hard to find an explanation for why we have been struggling in LaLiga but we need to get a move on."

(Reporting by Fernando Kallas in MadridEditing by Toby Davis)