NEW YORK (Reuters) - Boeing Co <BA.N> said on Tuesday that its next-generation 737 MAX jet will beat its previous fuel-efficiency target, delivering a 14 percent improvement, instead of the 13 percent gain promised earlier this year.

The 1 percentage point increase follows firm design configuration of the jet and completion of engineering reviews that confirmed the improvement over existing single-aisle jets, Boeing said on a conference call with reporters.

First delivery of the jet in the third quarter of 2017 is "on track," Boeing said.

The 737 MAX competes with the Airbus SA <EAD.PA> A320neo family of planes. Both are derivatives of current best-selling single-aisle aircraft with updated engines that are the main source of the fuel consumption savings.

(Reporting by Alwyn Scott; Editing by Maureen Bavdek)