The Argentine has lauded his side's mentality after recording victories in the Champions League and La Liga last week.
Oliver Torres, Diego Costa and Gabi got themselves on the scoresheet, while David Villa struck twice, to leave Atleti just a point behind leaders Barcelona.
And Simeone was delighted with the display of his men and said his players' mindset is making his job a far easier task.
"The players’ positive attitude is what makes us competitive," the 43-year-old told the club's official website. "The group accepts that the coach is looking for what the team needs to find the best possible way to win games. When a coach gets to work with a group like this it’s much easier to choose which players should play."
Simeone, 43, then reflected on the match, suggesting the opener by Torres might have caused complacency among the team initially.
"We started well and took an early lead and that made us lose a bit of our intensity. Until the 30th minute we found it difficult to take control of the match, even if Betis weren’t putting us in any danger," the manager said. "After the 35th minute we started to get back into our stride and in the second half, the team went all out for the win and put in a brilliant performance."