At one Met, on one side of Central Park, a gaggle of art dealers (Larry Gagosian, Robert Mnuchin), auction house executives (Lisa Dennison, Laura Paulson), critics (John Russell), and of course collectors toasted the artist Jeff Koons’s installation on the roof garden. It made for a spectacle that can be enjoyed until October 1 at the Metropolitan Museum of Art.

At the other Met, on the other side of the park, the gaggle was more diverse — and more dressy. It included art types (the artist

Chuck Close, auctioneer Tobias Meyer, art dealers Jeffrey Deitch and Roland Augustine, art critic John Richardson, the director of the Museum of Modern Art, Glenn Lowry, and of course collectors), and also celebrities dressed in Yves Saint Laurent, the sponsor of the gala.

The Metropolitan Opera House didn’t have the Metropolitan Museum’s outdoor vistas — the actress Eva Mendes, on the Grand Tier’s terrace, looked out on a Lincoln Center that is very much under construction — but it did have something beautiful to listen to and look at: the New York premiere of a new production of “La Fille du Régiment,” which included an encore by tenor Juan Diego Flórez and big performances by Natalie Dessay and Marian Seldes. And the opera event had a big take, too: Under the guidance of gala co-chairmen Mercedes and Sid Bass and Marlene Hess and James Zirin, the opera raised $1.7 million.

All in all, Monday was a good night for the Mets in town. Meanwhile, the city’s baseball Mets lost 7-1 to the Cubs at Wrigley Field before dropping another game yesterday afternoon.