WASHINGTON (Reuters) - Huntington Ingalls Industries Inc beat out General Dynamics Corp for a larger share of a $6.1 billion U.S. Navy order for nine new DDG-51 destroyers, with Huntington Ingalls set to build five ships for $3.3 billion over the next decade, the Pentagon said on Monday.

General Dynamics will build four DDG-51 destroyers for $2.8 billion over the next 10 years, it said. It also received an option for an additional warship, which if exercised, would bring the value of the company's contract to $3.5 billion, the Defense Department said.

The Navy said it planned to procure the 10th ship as part of its multi-year spending plan for fiscal years 2013 through 2017, and would work with Congress to resolve funding shortfalls resulting from mandatory across-the-board spending cuts before entering into that contract.

The Navy said the structure of the competition generated estimated savings of $1.5 billion, while allowing the shipbuilders and their suppliers to plan more efficiently for future work.

"These contract awards represent great value to the taxpayer and will ensure our warfighters have the ships and systems they need to prevail in any situation," said Navy Secretary Ray Mabus. "This award enables stability in our industrial base and ensures the Navy and the nation get the most efficient and affordable build plan for these destroyers."

(Reporting By Andrea Shalal-Esa; Editing by Bernard Orr and Steve Orlofsky)