Ruben Castro and Jorge Molina netted either side of the interval to give Real Betis the perfect start to the new year.
Betis are in the hunt for a return to European competition next season and they looked on course to strengthen their position when Castro slotted home against the run of play a minute before half-time.
Molina doubled their advantage just before the hour mark and although Paco Montanes pulled one back, Pepe Mel's side hung on to go level on points with fourth-placed Malaga after their third away victory in four matches.
Both sides still seemed to be in winter break mode in a tepid opening with neither team fashioning any chances in the opening half hour.
The game sprang to life when the hosts wasted two clear chances to break the deadlock.
First Helder Postiga, having rounded goalkeeper Adrian, was denied from slotting into an empty net by Betis defender Mario, while Alvaro Gonzalez headed narrowly wide from Antonio Apon's free-kick almost immediately afterwards.
And the Seville-based club took full advantage of those let-offs by taking the lead on the stroke of half-time, with Castro beating the offside trap to latch onto Benat's defence-splitting pass and place under Zaragoza keeper Roberto.
Javier Chica's long range strike stung the palms of Roberto before Betis went further ahead in the 58th minute.
Zaragoza defender Alvaro Gonzalez's attempted clearance was intercepted by Molina, who twisted and turned on the edge of the area before placing into the net.
Roberto kept Zaragoza in the game with a wonderful double save from Castro - parrying the striker's first effort and then denying him at the second attempt.
It proved invaluable for Zaragoza, who halved the deficit through Montanes' fine 20-yard strike in the 77th minute.
The 26-year-old's efforts were in vain as although the hosts pressed frantically for a leveller, they came away empty-handed for the third successive match at La Romareda.