Getafe defender Cabrera headed the Madrid side in front against an out-of-form Betis outfit in the 20th minute following a short-corner routine.
The visitors doubled their advantage just before halftime when Mata latched on to a through pass from strike partner Jorge Molina and calmly stuck the ball into the bottom corner.
Betis, who were knocked out of the Copa del Rey semi-finals by Valencia on Thursday, pulled a goal back in the 75th minute with a thumping finish from captain Joaquin and then had an effort from striker Jese ruled out for offside.
The Seville team were booed off the pitch at full time after a fourth defeat in eight games in all competitions, while some fans also chanted for coach Quique Setien to be sacked.
