Boston’s Kiké Hernández celebrates his two-run home run with Bobby Dalbec, second from right, and Travis Shaw, in the ninth inning of the Red Sox’ 5-3 win over the Washington Nationals on Saturday in Washington. Nick Wass/Associated Press

WASHINGTON — Christian Vázquez tripled home the tiebreaking run in the ninth inning and the Boston Red Sox moved to the brink of a postseason berth with a 5-3 win over the Washington Nationals on Saturday.

Boston is tied with the Yankees for the top AL wild card entering the final day of the regular season. The Red Sox will send ace Chris Sale to the mound Sunday needing a victory to punch a playoff ticket. If they win, they’ll host Tuesday’s wild-card game regardless of New York’s outcome because Boston won the season series 10-9.

“We know what that means if we win,” Boston Manager Alex Cora said.

If the Red Sox lose Sunday, they will still be assured entry into a tiebreaker game Monday. The Red Sox are a game ahead of Toronto and 1 1/2 clear of Seattle, with the Mariners set to play the Angels late Saturday night.

“Total team effort,” Cora said. “It wasn’t easy. … It hasn’t been easy all season.”

Tanner Houck pitched five perfect innings, striking out eight, but Washington tied the game at 1 in the eighth inning on Juan Soto’s long, bases-loaded sacrifice fly to center off Austin Davis (1-2).

J.D. Martinez led off the ninth with a walk for Boston, and Vázquez drilled a ball to right off closer Tanner Rainey (1-3) that easily scored pinch-runner José Iglesias for a 2-1 lead with two outs. Travis Shaw singled to drive in Vázquez, then Kiké Hernández homered into the Boston bullpen against Mason Thompson to push the lead to 5-1.

Washington’s Andrew Stevenson hit a two-run homer in the bottom of the ninth before Hansel Robles finished the game for his 14th save.

The Nationals loaded the bases with one out in the eighth after center fielder Hunter Renfroe lost a fly ball in the twilight, leading to a double, and Adam Ottavino walked two. Soto hit a soaring ball to deep center to tie it, but Josh Bell followed with a soft lineout to end the threat.

Soto said he thought Davis was “lucky” the ball was an out instead of a grand slam. Soto also said Davis was “talking trash” during the at-bat.

Rafael Devers’ 36th homer of the season put Boston in front 1-0 in the fourth. Devers struck out against Rainey with the bases loaded and two out in the eighth.

Houck zipped through the Nationals’ lineup, needing just 53 pitches to strike out eight among the 15 consecutive outs he recorded. Washington hit one ball out of the infield before Houck was lifted for pinch-hitter Christian Arroyo in the sixth.

Houck, a 25-year-old rookie, twice threw 90 pitches among his 13 starts this season. Both came in late August. He had not thrown more than 42 pitches in his last three appearances, all of which were in relief.

Before the game, Cora said there were no limitations on Houck, who pitched five innings three times earlier this season. He pitched into the sixth once, on Aug. 29.

“Didn’t struggle at all,” Cora said of the decision to remove Houck. “(Saturday) actually the plan was to see where Soto was and see where we went. He did an amazing job.”

“I’d much rather this team get a win and continue to go forward,” Houck said of the decision.

Gerardo Parra’s pinch-hit single in the sixth against Garrett Richards produced the Nationals’ first baserunner. Washington loaded the bases with two out in the seventh against Ryan Brasier, who was pitching for the fourth consecutive day, before Jordy Mercer struck out looking to end the threat. Mercer was ejected for arguing plate umpire Phil Cuzzi’s call.

Washington starter Josiah Gray pitched six innings, struck out seven and allowed a run.

NOTES

CORA SENT starting pitchers Nathan Eovaldi, Nick Pivetta and Eduardo Rodriguez a text Saturday morning.

‘Hey, man, spikes on,” he wrote to each of them, his way of telling them to be prepared Saturday and Sunday out of the bullpen if needed.

RIGHTY GARRETT Whitlock (right pectoral strain) threw a bullpen session Friday, but he was not activated from the injured list before Saturday’s game.

“We’ll see how he feels throughout the day and then we’ll see if he’ll be active tomorrow,” Cora said. “It’s a 50/50 chance. Obviously we have to think about the team and the roster and all that stuff. But also his health. So we’ll see how it goes today and what he can give us tomorrow if needed. And then we’ll make a decision.”

LEFTY JOSH Taylor – who is on the IL with low back strain – stayed in Boston. He initially was scheduled to meet the team here in D.C. on Friday.

“He’s not progressing as fast as we hoped,” Cora said. “So we still have to be patient with him.”