SAN FRANCISCO -- Max Scherzer ran his string of impressive starts to six Friday night and the Washington Nationals escaped a jam in the eighth inning with the first triple play in franchise history, holding on for a 4-1 victory over the struggling San Francisco Giants.

The win was the second in two days for the Nationals over the Giants in the matchup of division leaders.

Washington (61-42) moved six games up on the Miami Marlins and 7 1/2 ahead of the New York Mets in the National League East with their third win in four games to begin a three-city trip.

San Francisco (59-44) has the worst record in baseball (2-11) since the All-Star break.

Jayson Werth had two hits, drove in a run and scored another for the Nationals, who roughed up Giants starter Jeff Samardzija for four extra-base hits in six innings.

Scherzer (11-6) gave up a second-inning run on a pair of hits, but then shut out the Giants on just three more hits over the next five innings before leaving after having thrown 115 pitches.

The veteran right-hander allowed two or fewer runs for the sixth consecutive game, during which he's gone 3-1. He walked two and struck out six.

Down 4-1, the Giants threatened against the Washington bullpen immediately after Scherzer was pulled.

Denard Span led off the eighth inning with a bunt single against Nationals left-hander Oliver Perez.

Angel Pagan followed with a single, which brought Buster Posey off the Giants' bench as a pinch hitter, representing the potential tying run.

The Nationals countered with right-hander Blake Treinen, who walked Posey to load the bases with still no one out.

Washington manager Dusty Baker then called for lefty Sammy Solis, but with him grabbed Ryan Zimmermann from the bench and inserted him at first base.

Brandon Crawford hit Solis' second pitch on a line at Zimmermann, who reached down and caught it on the fly.

He easily doubled off Posey, who had strayed off first base, before throwing to third to complete a triple plan on Span, who had raced to home plate on contact.

The 3-3-5 triple play was the first in Major League Baseball history.

Left-hander Felipe Rivero gave up a two-out single to Gregor Blanco in the bottom of the ninth, and Trevor Brown greeted righty Shawn Kelley with a hit, setting the stage for Eduardo Nunez in his Giants debut.

But Nunez, acquired in a trade from Minnesota on Thursday, struck out on a full count to end the game.

Kelly was credited with his sixth save.

Daniel Murphy had a triple, and Werth, Wilson Ramos and Wilmer Difo collected doubles for the Nationals, who totaled eight hits.

Seven of the hits came off Samardzija (9-7), who gave up all four Washington runs in six innings. He walked two and struck out two.

Span, Pagan, Blanco and Conor Gillaspie had two hits apiece for the Giants, who out-hit the Nationals 9-8.

Samardzija went through the first 12 Nationals without giving up a hit. But once they starting coming, they often were loud.

Wilson Ramos ended the no-hit bit one out into the fourth inning with a double. He scored on Werth's first hit, a single, drawing the Nationals even at 1-1.

Werth earlier had walked, extending his streak of reaching base at least once to 32 consecutive games.

Difo, making his season debut, led off the Washington fifth with a double and scored on Ben Revere's single to put the Nationals on top.

Daniel Murphy made it a two-run inning and a 3-1 game with an RBI triple off the wall near the 421-foot marker in right-center field.

The fourth extra-base hit over an 11-batter stretch, a double by Werth, led to another Washington run in the sixth. He scored on Anthony Rendon's one-out single, making it 4-1.

The Giants scored first when Gregor Blanco singled home Gillaspie, who had doubled, in the second.

NOTES: Nationals manager Dusty Baker announced that RHP Reynaldo Lopez will be promoted from Triple-A Syracuse to start Saturday's game. Lopez failed to get out of the fifth inning in his only previous major league start July 19 against the Los Angeles Dodgers in an 8-4 loss. ... Baker also disclosed that C Pedro Severino, promoted from Triple-A on Friday, will catch Saturday's game. ... Severino took the roster spot created Friday when the Nationals put C Jose Lobaton (tendinitis in left elbow) on the 15-day disabled list. ... Giants manager Bruce Bochy said RF Hunter Pence (straight right hamstring) would be reinstated from the DL on Saturday and immediately re-inserted into the starting lineup. ... In order to create room on the 25-man roster for INF Eduardo Nunez, the Giants sent OF Jarrett Parker to Triple-A. ... The Giants took the field with a losing record (18-19) against teams better than .500. The game was the second of 23 against winning teams that the Giants will play over a 26-game stretch ending Aug. 25.