Diego Simeone believes Atletico Madrid are suffering from a major weakness due to a lack of clarity in attack after Los Rojiblancos slipped to a 1-0 defeat against Real Betis on Sunday.

Just three days after dismantling Betis 5-0 in the Copa del Rey quarter-finals, Atletico turned in an under-par performance at the Estadio Metropolitano as they were stifled by a disciplined defensive display from Manuel Pellegrini's side.

Antony's 28th-minute stunner from range was enough to condemn them to a loss, though Simeone's side did see a potential lifeline chalked off when Diego Llorente's own goal was ruled out following a VAR review for an offside against Antoine Griezmann.

The defeat ended Atletico's impressive 10-match home winning streak and handed Betis their first victory at the Metropolitano in eight games.

"The team struggles against teams that play deep, and it's not just [on Sunday]," Simeone admitted.

"We lack clarity in attack. It's a major weakness that we, as the coaching staff, haven't been able to overcome, but we'll work to give the team more tools.

"Betis played better than us; they defended very well. They didn't allow us to create scoring opportunities.

"They played better, defended very well, and counter-attacked well. They just played better. Congratulations to them."

The result leaves Atletico in third place, 12 points behind second-placed Real Madrid, who trail leaders Barcelona by a point following their win over Valencia.

Simeone was also asked about the performance of Julian Alvarez, who has now gone 11 matches without finding the net in LaLiga – his longest dry spell since arriving in Spain – though the Argentine quickly came to his compatriot's defence.

"I don't think it’s appropriate to keep commenting on Julian. We have faith in him," Simeone added.

"He's a very important player, the best we have. Hopefully, he can deliver for us in the important matches."