Second-half goals from Jorge Molina and Ruben Castro secured a first away win in the league for almost a year. Salva Sevilla and Papakouli Diop had traded first-half goals.
Betis had seemed destined for relegation at the start of the month, following a run of six defeats in seven, but they have enjoyed a profitable March to revive ambitions.
While Gabriel Calderon's side are still seven points adrift of safety, victory at Levante at least offers hope that any late push will not rely solely on their form at the Estadio Benito Villamarin.
The visitors were ahead after 13 minutes when Sevilla fired home from six yards.
Levante, whose Europa League ambitions now appear as good as gone, immediately tried to force a way back into the game as David Barral forced Betis goalkeeper Antonio Adan to tip his six-yard effort wide.
The Valencian side did draw level on 26 minutes through Diop as his 18-yarder, following an assist from Jordi, was too good for Adan.
Both sides missed chances to go into half-time ahead.
Betis striker Leo Baptistao shot over from 12 yards before Adan did enough to keep out Barral at close quarters.
Adan was kept busy after the break too, keeping out Pedro Rios' 25-yard shot.
The game was still level heading into the final quarter when Calderon's decision to send on Molina proved decisive.
The striker netted almost straight away, with 69 minutes on the clock, after latching on to a Baptistao assist.
Seven minutes later Ruben Castro made the points safe as he lashed in from close range and give Betis hope.