Diego Simeone accepted Atletico Madrid have to improve defensively after shipping four goals to Barcelona, but suggested Sunday's loss was equally down to his side's lack of cutting edge.

Atletico let an early lead slip as they lost 4-2 in a thrilling game at Camp Nou and dropped to fifth in LaLiga, two points behind opponents Barca in the final Champions League spot.

The reigning Spanish champions have now conceded 30 goals in 22 top-flight matches this season, which is already five more than in 38 matches last term.

It is just the third time Atleti have conceded four or more goals under Simeone in the league, with the first such occasion coming in December 2012 in a 4-1 loss to Barcelona.

Normally famed for their defensive solidity, Simeone admitted his side have not been good enough at the back this season.

"We've been defending well for 10 years but this year we have to improve. We don't have the necessary focus on defensive actions," he said.

"We haven't changed many players, except for [Kieran] Trippier, who left. They are playing the same ones that last year responded at a high level. 

"[Jose Maria] Gimenez and [Stefan] Savic have missed several games, but this time they played and we conceded four. 

"What counts is to work, try to improve and face the week with humility and push until the end."

Yannick Carrasco gave Atleti an early lead, but Jordi Alba's excellent volley, Gavi's header and a Ronald Araujo strike put Barca in control by half-time.

Dani Alves blasted in a fourth before later being sent off, at which point Luis Suarez had pulled one back against his former club, but Atletico's fightback ended there.

Simeone's side ended the match with an expected goals (xG) value of 1.21, compared to just 0.63 for Barcelona.

Indeed, that 3.37 differential between xG and actual goals scored is the biggest in a single LaLiga game this season of any team.

"I look at games in terms of scoring situations," Simeone said. "In the first half, Barca had four chances and scored three times; Atletico had four chances and scored once.

"The forcefulness of a side guarantees everything. Barca's forcefulness prevailed in the end.

"We started well, controlling possession and creating space for the forward players, who had chances. But beyond possession and counter-attacks, the most forceful team wins.

"In the second half we became more aggressive and intense. At 4-2 there was a feeling we could get into the game, but Barca defended low and we had fewer opportunities."

In a further blow for Simeone, it was confirmed after the game that new signing Daniel Wass suffered a torsion in his right knee and will undergo further tests on Monday.

On a day to forget for Atletico all-round, centre-back Savic – whose five interceptions was more than double that of any other player on the field – urged his team-mates to quickly pick themselves up.

"There is a lot of the season left and we are going to fight. We're worried about conceding so many goals, the number of them. Now we can only work and raise our heads," he told Movistar Plus.

"We wait to be behind to start playing. I don't know if it's a mental issue, but we have to change it if we want to be in the Champions League next year.

"Sometimes you work and things don't work out. We must keep going."

Atletico Madrid have confirmed the signing of utility player Daniel Wass from fellow LaLiga side Valencia on an 18-month contract.

The Denmark international, who was due to become a free agent at the end of the season, is reported to have cost Atletico €2.7million plus add-ons.

Diego Simeone's side confirmed the transfer on their official website on Thursday, making the Brondby youth product their first signing of the January window.

Wass is comfortable playing in a number of positions, including at right-back, where Atleti have been looking to recruit following Kieran Trippier's move to Newcastle United.

After three years at Celta Vigo, Wass made the switch to Valencia in July 2018 and featured 152 times – at least 12 times more than any other player for the club over that time.

Used predominantly in central midfield this term, the 32-year-old scored one goal and assisted another in 19 LaLiga starts for Los Che.

Wass has also been capped 41 times by his national side and played in five of Denmark's six matches en route to the semi-finals of Euro 2020 last year.