The Rojiblancos now have 71 points, 12 points behind leaders Barcelona, but are just three points ahead of their cross-town rivals Real Madrid.
Atlético need to show an improvement from the midweek performance against Real Sociedad.
"We have to keep fighting to improve ourselves and try to maintain our position in La Liga", Simeone said at a press conference on the eve of the Betis clash.
Atleti fielded a three-man defence for the stalemate at the Wanda Metropolitano - a formation they could use again when they face Arsene Wenger's side.
Elneny, 25, has enjoyed his best season yet in an Arsenal shirt, making 29 appearances in all competitions and proving a reliable performer when fit, as Wenger has rotated his central midfield options due to injuries and loss of form of other players.
How is Diego Costa?
The Armenian worldwide was hoping to be fit in time to face Atletico having returned to light training last week but Wenger says the game will come too soon for the playmaker.
Simeone said he thinks Costa is likely to return in the second leg of Europa League semi-finals on May 3, but cautioned that he was still waiting for the doctors' reports on his forward's recovery, reports Efe.
In truth, a lack of cutting edge was evident across the pitch, the end result proving more palatable to Betis, who appear safe in fifth and on course for Europa League group stage qualification.
"Ozil was sickness [flu] so I can not tell you much more about that".
Even though we have a small squad, our figures away from home have dropped. We have to isolate what the cause is and correct the problem both in LaLiga and the Europa League. With a team that has a big budget but nowhere near that of Barcelona and Real Madrid. They've won six straight matches and they've been playing good football.
"I am sure that Atletico will grow and we will see what will happen to me, for the moment I am here. Our travelling fans are the lifeblood of the club and we hope this measure helps to make their journey to Spain a little easier".