The veteran third baseman allowed a ground ball by Paul Janish to skip through his legs with two out in the eighth, enabling Steve Pearce to race home with the first of two unearned runs that gave the Orioles a 6-4 lead.
"I just misplayed the ball and felt terrible about it," said Longoria of the miscue that appeared destined to be the pivotal play of the game.
The Rays would cut the score to 6-5 in the home half of the frame courtesy of an Asdrubal Cabrera sacrifice fly, and they'd tie it on a dramatic, pinch-hit homer by Brandon Guyer off Baltimore closer Zach Britton to lead off the ninth.