Diego Simeone took a share of the blame for a 2-1 defeat at Athletic Bilbao and reiterated Atletico Madrid must show they have the "mental strength" to be crowned LaLiga champions.
Atleti's title hopes suffered a blow at San Mames on Sunday as Inigo Martinez's header four minutes from time consigned the leaders to what could be a costly loss.
Stefan Savic had equalised after 77 minutes, netting his first goal in the Spanish top flight for almost four years, after Alex Berenguer gave Athletic an early lead.
Martinez had the final say, though, nodding in a corner after being left unmarked to leave Atleti just two points ahead of Real Madrid and Barcelona, with Ronald Koeman's men able to take over at the summit if they win their game in hand.
Simeone says his side must show they have the right mindset to win the title.
Asked if Atleti were feeling the pressure, he said: "The Spanish championship is usually won by Barcelona and Real Madrid, except in 2014 or another year when we were close.
"For much of the season we had an advantage of many points, but we understood that Barcelona and Madrid were not going to get out of the title dispute. Sevilla also appeared.
"Whoever has more mental strength will be closer to winning."
Simeone brought on the fit-again Luis Suarez, Joao Felix and Thomas Lemar just before the hour mark, with Atleti looking short of ideas.
Former Argentina midfielder Simeone took some responsibility for a flat first-half performance.
"It is clear that if this is repeated it is more of a problem for the coach than for the team," Simeone said. "When a coach does not solve that situation, he is doing something wrong. We will try to improve."
Barca won 2-1 at Villarreal earlier in the day, following defending champions Real Madrid's goalless draw with Real Betis on Saturday.