Diego Simeone reflected on two points dropped despite seeing his Atletico Madrid side snatch a 1-1 draw seven minutes from time against city rivals Real.
Karim Benzema headed Real into a ninth-minute lead before his France international team-mate Antoine Griezmann had a first-half penalty saved for Atletico.
Real looked set to claim their first win at the Vicente Calderon in six attempts but Luciano Vietto came off the bench to net his first Atletico goal.
The hosts almost completed a remarakable turnaround when Keylor Navas made a brilliant injury time from Vietto's fellow substitute Jackson Martinez – a result Simeone felt would have been wholly merited.
"The feeling is that we lost two points," he told reporters. "We had more chances than Real Madrid.
"In the first half the team had two important chances – one for Angel Correa and the penalty.
"I do not think they have created scoring chances [apart from the goal] in the first half.
"It's an important point but the game was there to win."
The stalemate means Villarreal remain top of La Liga by a single point on a weekend where none of the top six in the Spanish top flight were victorious.
Simeone believes injuries suffered by the traditional heavyweights are playing a part in an exciting start to the season.
"Villarreal are doing a very good season," he added.
"Injuries are playing an important role. Teams are not the same without their best players.
"We have Koke out, Barcelona are missing [Lionel] Messi and [Andres] Iniesta, Real James [Rodriguez] and Danilo.
"We must adapt. At least this year is more entertaining."