MEXICO CITY, April 29 (Reuters) - Mexico's Alsea on Thursday reported a net loss of 312.1 million pesos ($15.3 million) in the first quarter, in a setback for the restaurant operator after it returned to profit at the end of last year.

Alsea, which operates Starbucks, Domino's and Burger King sites in South America and Europe, attributed the loss - which was steeper than a nearly 280 mln loss in the same quarter a year ago - to the ongoing impact of the coronavirus pandemic and store closures.

Revenue in the January-to-March period fell almost 16% to 10.21 billion pesos, it said in a statement.

Still, some quick-service brands were resilient, Alsea said. Sales at coffee chain Starbucks nearly doubled compared with the first quarter of 2019, before the pandemic. Alsea did not detail how Starbucks sales had fluctuated between 2020 and 2021.

"Starbucks keeps being a brand that has managed to adapt even better than we expected," Alsea said.

Delivery orders also rose, climbing nearly 65% compared with a year ago to represent nearly a third of Alsea's total sales.

Store closures in the period, both temporary and permanent, cost the company some 600 million pesos, Alsea said.

However, it saved about 880 million pesos by re-negotiating rents, reducing marketing and receiving aid from governments and franchise partners, it said.

($1= 20.4200 pesos at end-March) (Reporting by Daina Beth Solomon and Noe Torres; editing by Richard Pullin)