Diego Simeone hailed the importance of Diego Costa after the striker ended his six-month wait for a goal in Atletico Madrid's 2-0 win against Real Mallorca.

Spain international Costa headed home Koke's cross 26 minutes into Wednesday's LaLiga clash at Son Moix and Joao Felix added a second after the break as Atleti ended a three-match winless run in all competitions.

Costa had not netted since a 4-0 victory over Deportivo Alaves in March, but Simeone started him for a fifth straight game and hoped the goal boosts the 30-year-old's confidence.

"We know that strikers live on goals," he said at his post-match news conference. 

"It's very good for him and for the team. I'm happy because he needed the goal. He's one of our most important players in attack and if our forwards play well then it's easier to win."

A 2-0 loss to Real Sociedad and 0-0 draw with Celta Vigo saw Atletico slip down the table, but victory over Mallorca moved them back into second.

"We're improving the balance of the team," Simeone said. "We had a good first half and in the second half Mallorca attacked but we defended well."

It was not all good news for Atletico, however, as substitute Alvaro Morata was sent off for two yellow cards in quick succession eight minutes after replacing Costa.

Morata, who clashed with Mallorca skipper Xisco Campos and rowed with the referee to earn his dismissal, will miss Saturday's derby against his former side and LaLiga leaders Real Madrid.

Asked if the sending off was fair, Simeone replied: "I did not see what happened well. 

"For some reason he reacted. I cannot anticipate what happened. I saw that he was arguing with one player and thought they'd both be dismissed."