WASHINGTON -- Tanner Roark took a shutout into the ninth inning, Anthony Rendon had two hits and two RBIs and Stephen Drew had three doubles and scored twice as the first-place Washington Nationals beat the Pittsburgh Pirates 6-0 Saturday.

Rendon, batting cleanup for the first time this year, had his first homer since July 7 when he went deep in the fifth inning. Drew started at second base in place of the injured Daniel Murphy and now 15 of his last 25 hits are for extra bases.

Roark (9-5), who had an RBI single, yielded just five hits in eight innings plus two batters. He left after allowing a single and hit by pitch to start the ninth, and Blake Treinen came on to get the last three outs.

Roark threw his only shutout April 25, 2014 against the San Diego Padres. He struck out five Saturday and got a big ovation from the sellout crowd of 38,861 when he came to bat in the eighth and again when he left in the top of the ninth.

The losing pitcher was Pittsburgh's Gerrit Cole (5-5), who has not won since May 20 against the Colorado Rockies. He has lasted seven innings in just two of 13 starts this season.

Washington (56-36) has won five games in a row and is a season-best 20 games over .500. The Pirates (46-45) have lost three in a row after winning seven of eight. The Nationals have won eight of the last nine starts by Roark, who has not lost at home since May 25.

Andrew McCutchen had two hits for the Pirates, who will try to prevent a three-game sweep against Washington starter Max Scherzer on Sunday.

The Nationals scored a run in the first and could have had more.

Rendon had an RBI single to make it 1-0 but Bryce Harper, who had singled, was thrown out at third on the hit for the second out. The next hitter, Clint Robinson, smoked a blast to the gap in right-center but Sean Rodriguez made a diving catch on the warning track for the third out.

Danny Espinosa had an RBI double in the second to give the Nationals a 2-0 lead. His hit scored Drew, who doubled with one out.

Washington made it 4-0 in the fourth, thanks to some poor defense and good base running.

With the bases loaded, Roark reached on an infield single to drive in a run and the throw by second baseman Josh Harrison landed in the Washington first-base dugout to allow a second run to score.

The Nationals' third run in the inning came when Espinosa scored from third on a fielder's choice off the bat of Ben Revere off starter Cole.

Rendon hit a solo homer in the fifth -- his 10th of the year -- off reliever A.J. Schugel to make it 6-0. The Nationals now have seven players with at least 10 homers.

Cole lasted just four innings and allowed seven hits and five runs. He last pitched in the majors June 10 against the St. Louis Cardinals when he went just two innings and allowed two hits and no runs while throwing 35 pitches.

NOTES: The start of the game was delayed one hour and 11 minutes by rain, which created a scenic rainbow beyond the right-field foul pole at game time. ... The official scorer made a change in Friday's game. A bunt by Washington RHP Stephen Strasburg remained a sacrifice and RBI but an error was taken away from Pittsburgh 1B David Freese and ruled a fielder's choice. ... Pittsburgh RHP Gerrit Cole (5-4, 2.77 ERA) came off the disabled list Saturday to start against the Nationals. 1B Josh Bell, who made his major league debut July 8, was sent to Triple-A Indianapolis to make room for Cole after he went 2-for-2 for the Pirates in four games. ... Washington RHP Max Scherzer (10-6, 3.03 ERA) will face Pirates RHP Chad Kuhl (1-0, 6.08) in the series finale on Sunday. Scherzer threw a no-hitter at home against the Pirates on June 20, 2015. ... Washington 1B Ryan Zimmerman, who has been on the disabled list since July 8 with a left rib cage strain, took ground balls during batting practice. ... Washington 2B Daniel Murphy, who is hitting a league-high .348, was out of the starting lineup for the second straight day with a bad hamstring, according to manager Dusty Baker. ... Pittsburgh RHP Ryan Vogelsong (1-1, 3.74 ERA), who is on the disabled list with facial fractures, was in the Pittsburgh clubhouse before the game after he threw in a minor league rehab assignment Friday for Double-A Altoona against Harrisburg, a Washington affiliate. Pirates manager Clint Hurdle expects Vogelsong to throw off flat ground on Sunday and make another minor league outing the middle of next week.