BOSTON – Of all the things that have gotten in the way of the Twins' push for a postseason berth, first base and a first baseman have to be among the most unexpected.

A first-inning slow roller by Boston's Romy Gonzalez collided with the bag, turning an easy out into a freak-play single, and that hit wound up extending the inning far enough to allow Red Sox first baseman Triston Casas to bat with two runners on base. Casas clobbered the first pitch he saw from Pablo López into the right-field seats, the first of a trio of blasts he hit in Sunday's Game 1 of a doubleheader, and the Red Sox handed the Twins their 12th loss in 18 games, 8-1 at Fenway Park.

"There's no sugarcoating it — not the performance I was looking for, especially with what this game means," said López, who tied his season-high by giving up seven runs in only four innings. "Didn't provide length, didn't provide quality. I didn't do my part."

The loss knocked the Twins out of a playoff berth, at least temporarily, once Detroit completed a 4-3 victory in Baltimore, improving the Tigers to 82-74, a half-game ahead of the 81-74 Twins. Kansas City lost its seventh consecutive game on Sunday and also stands at 82-74, though the Royals hold a tiebreaker over Detroit.

No, it's probably unlikely that the Twins would have won if not for the way first base prevented Carlos Santana from fielding Gonzalez's ball, but it eventually played into one of López's seasonlong weaknesses: He allows first-inning home runs. Casas' shot was the eighth López has given up, one fewer than Crawford, the American League leader.

Casas proved it was no fluke two innings later, when he batted again with two Red Sox on base. This time he waited for a López fastball, and when he got one in the strike zone on a 2-2 count, he pounced, driving it into the second row of fans atop the Green Monster in left field.

"The 2-2 is always an action pitch. You want to make sure it's quality, but you don't want to put yourself in a 3-2 count and load the bases," López said. "It's a fine line of execution. … I didn't make a quality pitch, and he's got power to all parts of the park."

In the fifth, with Brent Headrick making his 2024 debut for the Twins, Casas greeted the lefthander by smashing his second pitch into the center field seats just beyond the Red Sox's bullpen, his third of the day and 12th on the season.

"We have to forget it. Don't let it define you, don't let it get in the way of your process," López said. "I know the clubhouse right now is looking to the next one. That's my mentality, too. I know I'm going to get another one that could be just as meaningful as this one, if not more. I've got to turn the page."

The Twins, on the other hand, were just as feeble at the plate as they have been on this entire road trip. The Twins managed only four hits against Red Sox starter Nick Pivetta, all of them singles and never more than one in an inning. They left the bases loaded in the first inning before Casas' first home run, and their lone run scored on an error by Gonzalez, allowing Willi Castro to score from third base.

Boston's bullpen didn't give up a hit over the final four innings, and except for a walk that was immediately erased by a double play, the final 13 Twins went down in order.