Madrid: Real Madrid lost their first La Liga game of the season going down 3-2 at city-rivals Rayo Vallecano on Monday to leave Barcelona two points clear at the top.
Rayo took an early lead in a see-saw game before Real went 2-1 ahead. Rajo equalised before half-time before winning the match with a twice-taken penalty from Oscar Trejo in the 67th minute.
After 13 matches, Barcelona are top on 34 points to Real Madrid's 32.
Barcelona and Manchester United will face each other in the Europa League knockout round play-offs following Monday's draw.
Barca were eliminated from the Champions League group stage to drop into the Europa League for the second season running, while United came second in their Europa League group.