BOSTON (Interstat) — A four-run third inning by the Boston Red Sox was quickly erased by a potent San Diego Padres offense, which used a three-run fourth and a three-run homer from Manny Machado in the fifth to seize control and secure an 8-6 victory Sunday in the rubber match of a three-game series at Fenway Park.

The win, played before an afternoon crowd of 29,240 in a game that lasted 2 hours, 54 minutes, improved the Padres to 4-5 on the young season, while the struggling Red Sox fell to 2-7.

The most important sequence of the game came in the top of the fifth inning, directly answering Boston’s earlier outburst. After the Red Sox had sent nine men to the plate in the third to take a 4-0 lead, the Padres chipped away with three runs in the fourth. In the fifth, with two on and two out, Machado turned on a pitch from reliever Tyler Uberstine and launched a three-run home run over the Green Monster in left field. The blast, Machado’s first of the year, gave San Diego a 6-4 lead it would not relinquish, completely shifting the game’s momentum after Boston’s early advantage.

Boston starter Ranger Suarez navigated three scoreless innings but ran into immediate trouble in the fourth. Fernando Tatis Jr. led off with a double and scored on a Jackson Merrill single. After a Machado single, Uberstine entered and recorded a strikeout but then walked Xander Bogaerts to load the bases. Nick Castellanos delivered a two-run single to center, cutting the deficit to 4-3.

Uberstine was charged with the loss, his first of the season, after allowing one earned run on three hits over 2 2/3 innings of relief.

The Padres added insurance late. Merrill led off the eighth with a solo homer, his second of the year, to make it 7-4. After Boston rallied in the bottom of the seventh on a two-run double by Masataka Yoshida, San Diego got that run back in the ninth on a sacrifice fly by Tatis.

Yoshida was a bright spot for Boston, going 3 for 4 with a double and three RBIs. Wilyer Abreu also had three hits, including an RBI triple in the third.

San Diego’ bullpen was critical in preserving the lead. After starter Kyle Hart was pulled in the third, Bradgley Rodriguez, Jeremiah Estrada and Mason Miller combined for 4 1/3 innings of one-run relief. Estrada earned the win, his first of the season, with a scoreless seventh inning. Miller overpowered the Red Sox in the ninth, striking out the side to record his fourth save of the year.

The game’s outcome defied pregame projections. Interstat’s game simulator had predicted a 3-2 Boston victory, and its ELO system gave the Red Sox a 51.3 percent probability to win. Boston had been installed as a 1.5-run favorite, and the combined 14 runs sailed over the posted over/under line of 9.

The Padres now head to Pittsburgh for a three-game series beginning Monday, looking to climb above .500. The Red Sox, mired in an early-season slump, will welcome the Milwaukee Brewers to Fenway Park for a three-game set starting Monday.