PHILADELPHIA -- Phillies interim manager Pete Mackanin doesn't have an answer why his ballclub's bats have suddenly come to life.

After hitting the eight-run mark just once over the first two and a half months of the 2015 season, Philadelphia has done it four times in a week's span.

It happened again Sunday, with Cesar Hernandez's four-hit game leading the way in an 8-5 win over the Washington Nationals to salvage a doubleheader split.

"It's a funny game," said Mackanin, who took over for Ryne Sandberg after Sandberg resigned from his position Friday. "I don't have the magic potion--if I did, I'd give everybody some of it."

In the opening game, Washington got seven strong innings from starting pitcher Stephen Strasburg to hold on for a 3-2 win.

The Nationals (42-34) did not get that same effort from Tanner Roark in the series finale as their eight game-winning streak was halted.

Roark, who was announced as the starter only 30 minutes before the game, was chased after just 3 1/3 innings, giving up 12 hits as he was responsible for eight runs -- all earned. The Phillies (27-50) batted around twice at least partially under his watch, in the second and fourth innings, scoring four runs in each frame.

"Not his day," Nationals manager Matt Williams said of his starting pitcher. "They did a nice job of staying on baseballs and making contact and hitting it to the middle of the diamond. A lot of grounders today that got through the infield, a couple of balls off the end of the bat."

It was difficult to find a Phillies player who wasn't getting involved in an offense that picked up only five hits in the opening game of the day but collected 16 base hits off the Nationals' staff in the second game.

Phillies second baseman Cesar Hernandez went 4-for-4 with a stolen base after going 2-for-4 with two steals in the first game. Center fielder Odubel Herrera, who watched the opener from the bench, went 3-for-5 with two runs scored and an RBI. Third baseman Maikel Franco, first baseman Darin Ruf and left fielder Cody Asche had two hits apiece.

Even starting pitcher Severino Gonzalez got in on the action, collecting his first major league hit and coming around to score in the fourth inning.

"You've heard that cliche that hitting is contagious--and it is, once you get around guys that are getting hits, it just seems to happen," Mackanin said.

Gonzalez, who was called up from Triple-A Lehigh Valley for the start, was removed in the sixth inning after allowing a home run to Nationals' catcher Jose Lobaton. He still picked up his third win of the season by going 5 1/3 innings, allowing four runs (all earned) on six hits while striking out seven.

After the game, it was announced that he would be headed back to the minor leagues, but he was certainly satisfied with his effort both on the mound and behind the plate.

"I was hoping that I would get a chance to get a base hit," he said through a clubhouse translator. "I'm feeling very good, especially about the opportunity that I got to come over here and pitch today."

The Nationals got within three runs by tacking on one in the seventh, but aside from a three-run fourth inning it was a struggle to string together hits with regulars Bryce Harper, Denard Span and Wilson Ramos all sitting this one out.

Phillies closer Jonathan Papelbon worked around a two-out single for his 14th save in as many opportunities.

Washington will try to start a new winning streak on Tuesday in the opener of a three game series in Atlanta. The Phillies begin a four-game set with Milwaukee at home on Monday.

NOTES: The Phillies and Nationals managed to play 1 1/2 innings of Saturday's game before it was canceled due to rain. Sunday's game, originally scheduled to start at 1:35 p.m. ET, was moved up to 1:05 p.m. and became the first of a single-admission doubleheader, the first true doubleheader in Philadelphia since Sept. 3, 2006. ...With a loss in the opening game of the doubleheader, the Phillies became the first team to lose 50 games this season. It's the quickest the franchise has reached 50 losses (76 games) since the 1997 season, when they started the year 23-50. ...Washington added INF Wilmer Difo to the active roster as its 26th man for the doubleheader.