WASHINGTON -- Manager Dusty Baker toyed with the Washington Nationals' batting lineup in the first eight games of the season, partly because of injuries and also to see who fits in the best spots.

However, the veteran skipper has no plans to mess with his third and fourth hitters -- lefty sluggers Bryce Harper and Daniel Murphy.

Harper reached base four times and Murphy had four hits and drove in five runs as the Washington Nationals beat the struggling St. Louis Cardinals 8-3 on Tuesday in the second game of the three-game series.

"They can be as good as there is in baseball," Baker said of the productive tandem. "They both walk. They both hit left-handers. They both hit right-handers."

Mainly they just hit.

Murphy, who tied his career highs the four hits and five RBIs, has hit safely in the first eight games, producing a .472 average. Harper has reached base 10 times in the past two games and is hitting .393.

The Nationals hit three home runs off St. Louis starter Lance Lynn, who gave up long balls to Jayson Werth, Matt Wieters and Murphy.

"He is being careful (against Harper)," St. Louis manager Mike Matheny said of Lynn, who walked Harper all three times. "It is a good lineup. They are rolling and rolling in a good direction right now. They got hits when they needed the big hits. They got the best of us. It is a good offense. They jumped on the right pitches at the right time."

"I wasn't trying to walk him, ever," Lynn said of Harper. "I just didn't make any pitches against him. That was pretty much it. At no point was I trying to walk him. I just did. I had pretty good stuff all night. There was three mistakes. Three mistakes left the yard. That's pretty much it. That happens."

And the Cardinals are reeling, having lost six of eight.

"We need to be better," Matheny said of his defense, which made two errors and had other miscues. "That is all there is to it, all the way around."

Wieters (.435) had two hits for the Nationals, who entered the game with a league-best .308 average. Harper walked in his first three at-bats to extend his on-base streak to nine in a row, which tied a personal best. He was later retired on a fielder's choice but doubled in the eighth.

Washington starter Gio Gonzalez (1-0) allowed two runs (one earned) on six strikeouts and no walks in seven innings.

"He used everything. He kept guys off balance," said Matheny, a former catcher.

Said Baker of Gonzalez: "He threw an outstanding game. He kept his composure. His breaking ball was good. He threw an outstanding game for us. We need Gio. We knew that before the season started."

Lynn (0-1) gave up six runs (four earned) and five hits in five innings.

Jose Martinez and Aledmys Diaz each had two hits for the Cardinals, who allowed 22 runs and 30 hits in the first two games of the series.

The Cardinals took a 1-0 lead on an unearned run in the first as Yadier Molina had a sacrifice fly to drive in Dexter Fowler.

Murphy had a two-run single with the bases loaded in the third as Washington took a 2-1 lead.

St. Louis responded with a solo homer by Randal Grichuk in the fourth to tie the game at 2 off Gonzalez.

But Werth led off the last of the fourth with a solo homer to give the Nationals a 3-2 edge. Two batters later Wieters lined a solo homer to right to make it 4-2.

Murphy came through again in the fifth as he cranked a two-run homer to right off Lynn to make it 6-2.

"Murphy is unreal. He is just on fire," said Gonzalez, who added it was as if Murphy were hitting watermelons or beach balls. "The guys did a great job of swinging the bat one through eight. I was just fortunate enough to be on the winning side of the game."

Murphy doubled and scored on an error in the seventh to give the Nationals a 7-2 lead. Diaz hit a solo homer off Joe Blanton in the eighth to make it 7-3, but Murphy had a RBI double to plate Harper in the eighth for an 8-3 lead.

NOTES: Cardinals INF Matt Carpenter did not start because of back stiffness but pinch-hit in the ninth and walked. ... Washington RHP Max Scherzer (1-0, 2.70 ERA) faces St. Louis RHP Mike Leake (0-1, 1.13) in the series finale Wednesday. ... Washington SS Wilmer Difo made his first start of the year after Nationals SS Trea Turner went on the disabled list Monday with a right hamstring strain. Difo went 1-for-5.