PITTSBURGH -- Gerrit Cole does not spend a lot of time looking at the stat sheet, but he does know that he leads the major leagues with 14 wins.

The Pittsburgh Pirates right-hander pitched into the eighth inning and second baseman Neil Walker homered as the Pirates beat the Washington Nationals 3-1 on Sunday.

"It's really special," Cole said. "I try not to reminisce or focus on it right now. We've got four months in the offseason to do that kind of stuff.

"It's been a collective effort to get the wins where they are. Obviously there's a lot of different factors that can go into that but they wouldn't be where they are if it wasn't for how well we've played as a team, wasn't for the effort that those guys give me every time I step on the mound."

Cole (14-4) allowed one run and seven hits in 7 2/3 innings with eight strikeouts and no walks against the National League East-leading Nationals as he became the first Pirates pitcher with 14 wins by the end of July since Dock Ellis was 15-4 in 1971.

Cole kept his record perfect against the NL East this season as he is 6-0 with a 1.26 ERA in six starts. Cole also improved to 7-1 with a 1.84 ERA in eight day starts and 9-2 with a 2.15 ERA in his last 12 overall outings.

"Tough customer against us today," Nationals manager Matt Williams said.

Nationals right-hander Jose Ross (2-3) had his streak of 29 2/3 innings without allowing a homer to begin his career ended when Walker, a switch-hitting second baseman, connected to lead off the fourth.

Walker's ninth homer of the season extended the Pirates' lead to 3-1.

Mark Melancon pitched a perfect ninth inning for his major-league-leading 32nd save in 33 chances.

The Pirates (57-41) won three of four in the series and notched their 11th win in their last 13 home games at PNC Park, where they are 14-2 against NL East teams this season.

Pittsburgh entered the day leading the NL wild-card standings by three games over the San Francisco Giants but cut its deficit to six games in the NL Central when the first-place St. Louis Cardinals lost to the Atlanta Braves, 3-2.

The Nationals (52-45) had their lead trimmed to two games over the New York Mets in the NL East.

Ross gave up three runs and five hits in six innings while striking out seven and walking one. He has 34 strikeouts and three walks in his first five career starts.

"He was OK," Williams said of Ross. "He left a ball up 2-0 to Walker but I thought he pitched well. He gave us a chance. It was one swing. Other than, he was pretty good. He kept us in the game."

Rookie center fielder Michael Taylor accounted for the Nationals' lone run when he homered with two outs in the third inning to open the scoring. It was Taylor's second homer in as many days and eighth of the season.

The Pirates countered in the bottom of the third with RBI singles by right fielder Gregory Polanco and center fielder Andrew McCutchen to take a 2-1 lead.

Nationals second baseman Danny Espinosa had two hits.

All four games of the series were sellouts, and the total attendance of 151,952 was a record at PNC Park, which opened in 2001.

"The Nationals have good hitters up and down the lineup, so it's an accomplishment to take three of four from them," Melancon said. "We can feel good about that."

NOTES: Washington 2B Anthony Rendon was not in the lineup a day after being activated from the disabled list, but he had a pinch-hit single in the eighth inning. Manager Matt Williams plans to ease Rendon back into action slowly after he missed a month with a left quadriceps strain. ... Nationals SS Ian Desmond extended his hitting streak to seven games and RF Bryce Harper reached base in a 23rd straight game. ... Pittsburgh CF Starling Marte ran his hitting streak to seven games while SS Jung Ho Kang's streak ended at seven games. ... Pirates 3B Aramis Ramirez was 0-for-3 and is hitless in seven at bats in two games since being acquired from Milwaukee in a trade. ... Both teams are off Monday before opening road series Tuesday night. Washington RHP Jordan Zimmermann (8-5, 3.30 ERA) will face Marlins RHP Jose Fernandez (3-0, 2.77 ERA) at Miami while Pittsburgh RHP Charlie Morton (6-4, 4.59 ERA) will oppose Minnesota Twins RHP Mike Pelfrey (5-7, 3.94 ERA) at Minneapolis.