The game looked bleak for the San Diego Padres as the bottom of the eighth inning started on Tuesday night. They trailed the visiting Washington Nationals 4-1 and had just three hits against a team using a bullpen game with one of the worst bullpens in the majors.

Then reality set in. Washington's Jared Simpson walked the bases loaded and teed up a four-run rally that enabled San Diego to pull out a 5-4 win and stay within a half-game of Arizona for the National League's last wild-card spot.

San Diego will shoot for a series sweep of the Nationals when the Padres end a six-game homestand on Wednesday afternoon.

That San Diego (77-68) would rally late for a win is not a surprise. It's done so 38 times this year, the fourth-highest total in the majors. And third baseman Manny Machado said he knows why it's happened so often.

"We just know we have the bullpen to hold down the game and the offense to score some runs," he said. "It was unselfish baseball -- guys passing the baton, taking their walks and getting some runs. Unbelievable at-bats by some dogs on our team."

Machado might have had the biggest one. Fouling off three consecutive fastballs from Erik Tolman, he delivered a 2-2 single up the middle that scored two runs to tie the game. Three batters later, Machado came home from second on Luis Campusano's tie-breaking bloop single to right-center.

Even though Machado has needed a hot streak lately to push his batting average to .226, manager Craig Stammen has never lost faith in his ability.

"There's a reason 40,000 fans are here tonight, and it's because when he takes an at-bat, something like that might happen," Stammen said.

Walker Buehler (8-6, 4.56 ERA)will start for San Diego on Wednesday. The right-hander is coming off a good outing Friday against the New York Yankees, allowing just one run on three hits in five innings during his team's 3-2, 10-inning win. Buehler is 3-1 with a 2.67 ERA in six career outings against Washington.

The Nationals will counter with rookie Jackson Kent (1-3, 5.55 ERA), who absorbed a 5-3 loss Friday at the Los Angeles Dodgers. The left-hander gave up four hits and four runs, three earned, in five innings with four walks and four strikeouts. This will be his first career start against San Diego.

Washington (67-80) is 0-5 on its Southern California road trip and has lost six straight games, the last five by one or two runs. The Nationals set a major league record Tuesday night by blowing their 38th save of the year.

Left-handers Simpson and Tolman blew a 4-1 lead in the eighth. In addition to Simpson walking the bases loaded, Tolman couldn't keep the inherited runners from scoring, then allowed the winning run later in the inning.

The latest loss erased bright spots such as three perfect innings from Washington opener Riley Cornelio, as well as homers from Yohandy Morales and Andres Chaparro. For first-year manager Blake Butera, the season's remainder will serve as an evaluation ground to see what his young players need to take the next step for future seasons.

"Part of our job this year was to really look at who could benefit from things like seeing what guys can add 2 mph or add some bat speed," he said.

--Field Level Media