BOSTON - Dean Kremer appeared to be the victim tonight of bad luck, two-out execution and run support in a ballpark that’s treated him rudely. Someone needed to have his back, and Anthony Santander stepped up with a game-tying homer off Red Sox reliever Justin Slaten with two outs in the eighth inning.

Only Kremer could be saved. A game was lost in sudden and harsh fashion, another stumble by the Orioles that also cost them ground in the division race.

Emmanuel Rivera did his part earlier with a solo homer in the third inning and he came up big again much later, but Tyler O'Neill hit a three-run homer off Keegan Akin in the 10th to give the Red Sox a 5-3 walk-off win over the Orioles before an announced crowd of 32,448 at Fenway Park.

The Orioles have lost four of their last five games and five of seven while falling to 83-64, including 25-26 since the break. The Yankees beat the Royals 4-3 in 11 innings to open a 1 1/2 game lead.

An off-day Thursday is followed by a three-game series in Detroit to finish the penultimate road trip of the season.

The start to the Orioles' latest homestand, which began with them playing easily the worst team in the majors, could have gone better.

Right-hander Corbin Burnes, who began today with an 8.59 ERA over his last three starts and 7.36 over his past five, gave up a couple of soft hits and both runners scored in the top of the first to give the Chicago White Sox a 2-0 lead.

One of those two runs was unearned, thanks to an error by first baseman Ryan O’Hearn, and the O’s gave up 90 feet on the bases overthrowing the cutoff man. Not a sharp start to the series.

They were playing a White Sox team that fell to 31-107 with Sunday's defeat to set a franchise record for losses. They had lost 10 in a row and 14 of 15, and were 4-40 the last 44 games.

They came to Baltimore with the second-worst major league record after 138 games since the Philadelphia A’s (30-107-1) of 1916.

Last fall, he was playing in the World Series for the Diamondbacks. It capped a 2023 season that began with him playing for Puerto Rico in the World Baseball Classic. It ended chasing a championship.

He went 2-for-5 with two runs and two RBIs in the World Series versus the Rangers, who won the World Series in five games.

But on Monday, corner infielder Emmanuel Rivera was designated for assignment by the Marlins. The Orioles claimed him two days later and now he is with them waiting for his first chance to play for his new team.

A right-handed hitter, Rivera, 28, played in 96 games with Miami, taking 229 plate appearances and batting .214/.294/.269/.563. He has a career .656 OPS over 313 big league games with Kansas City, Arizona and Miami.

“I think it’s a great opportunity,” he said of his chance with the O’s, with interpreting help from Brandon Quinones. “Thank God, you know, for being able to stay healthy and that I’m now here with this team.