Carlo Ancelotti said "football people don't understand" penalties like the one awarded to Atlético Madrid in their 1-1 derby draw with Real Madrid on Saturday.

Julián Álvarez converted the 35th minute spot kick -- given by VAR after Aurélien Tchouaméni was adjudged to have fouled Samuel Lino -- to put visitors Atlético ahead at the Bernabéu.

Kylian Mbappé equalised in the second half, for a result which leaves leaders Madrid just a point ahead of their local rivals at the top of the LaLiga table.

Ancelotti initially said "I'll pass" when asked for his thoughts on the penalty, after a week which saw Madrid file a formal complaint over the refereeing in their defeat at Espanyol last weekend, drawing an angry response from Atlético, who accused them of putting pressure on officials.

Madrid have been regular critics of refereeing in LaLiga, and their open letter this week called for "structural reform" calling the current system "completely discredited."

"I think we deserved more," Ancelotti said. "We had total control, we scored, we got into the box, we played very well in the second half.

"The first half was totally different, much slower, and less aggressive. I think with what we did in the second half, we leave with a good feeling. The penalty affected the team, obviously."

"I think the referee did his best with his decisions," Diego Simeone said in his news conference, citing a first-half decision to show Real midfielder Dani Ceballos a yellow card for a challenge on Pablo Barrios. "For some people the Ceballos challenge was a red, and for others it wasn't. I thought [the referee] had an OK game."