Diego Simeone remained positive despite seeing Atletico Madrid's club-record 15 game winning run across all competitions come to an end against Leganes. 

Matija Nastasic's header four minutes after the break proved to be the difference at the Estadio Municipal de Butarque, despite Atletico dominating much of the game.

Simeone watched on as his side generated an expected goals (xG) total of 2.52 from their 19 attempts, compared to their opponents' 0.41 from their nine shots. 

Julian Alvarez and Antoine Griezmann both struck the woodwork, with the latter missing a penalty late on, dragging his effort wide of Marko Dmitrovic's net. 

"The team generated enough situations to have had a different scoreline," Simeone told a press conference.

"We started with a lot of energy, with key plays in which we could have found the goal.

"In the second half they made good use of the dead ball, and after they scored they started defending better, with humility, and we found it difficult to overcome that.

"We had that penalty, but Leganes did very well. It was our turn to lose."

Simeone insisted that he was not worried about how the result would impact his players' mentality, having last lost a game back in October against Real Betis. 

The defeat keeps them at the summit of the LaLiga standings, with second-placed Real Madrid in action against Las Palmas on Sunday and only a point behind them.

Barcelona, meanwhile, were unable to capitalise on Atletico's slip after they were held to a 1-1 draw against Getafe at the Estadio Coliseum. 

Atletico's winning run across all competitions was their longest in the club's history, with Simeone eclipsing his own record of 13 consecutive wins from 2011-12. 

"When you get used to winning, then it's harder to lose because it's very nice. Obviously, it hurts to lose, but it's part of the way, and you have to accept it," Simeone said.

"We had 15 extraordinary games, with the great joy of having generated the best record in the history of Atletico. The journey was fantastic, and I can only say positive things about my players' huge effort to achieve that.

"Today I stick with their performance, which was good and hope we can keep playing well moving forward."