The evening began on a high note for Mars, who, alongside Anderson .Paak, won Best Pop Duo/Group Performance for their collaboration “Leave the Door Open.” This victory brought his tally to 15 wins without a single loss. However, the tide turned during the Song of the Year announcement when Kendrick Lamar’s “The Heart Part 5” was awarded the honor, leaving Mars with a bittersweet feeling as he reflected on his unexpected defeat.