PHILADELPHIA -- Chicago Cubs manager Joe Maddon shook the hand of pitcher Jon Lester as he returned to the dugout after crafting eight shutout innings against the Philadelphia Phillies on Monday night.

Lester's night was over. The game was not, however.

The Cubs' 6-4 victory wasn't secure until reliever Hector Rondon retired pinch hitter Ryan Howard with a runner aboard to end it.

Philadelphia's Freddy Galvis hit a three-run homer off Justin Grimm and Tommy Joseph followed with a solo shot off Rondon in the ninth.

"That's why they call them the Fightin' Phils, right?" Chicago manager Joe Maddon said.

The Cubs, meanwhile, continue to be the major leagues' best team. Lester (7-3) won his third straight start and Jason Heyward hit his 100th career homer for Chicago, which won for the fifth time in six games to improve to 40-16.

Dexter Fowler and Kris Bryant had three hits apiece and Anthony Rizzo drove in two runs for the Cubs.

"That's the kind of team we have," Heyward said. "I feel like anybody can do it from any spot (in the lineup). I feel like there's no true break."

Lester yielded four hits while striking out nine. He didn't walk a batter, and he retired 18 of the last 19 hitters he faced, including 13 in a row between the second and sixth innings.

"I just got into a better rhythm as the game went on," said Lester, who allowed three singles in the second inning alone.

Lester, who earned a 6-2 victory over Philadelphia on May 27, improved to 6-0 with a 1.46 ERA in eight career starts against the Phillies, and 4-0 with a 1.29 ERA in five outings at Citizens Bank Park. He also contributed his second hit of the season Monday, a fourth-inning double. He then scored when Heyward homered.

Lester threw 95 pitches in his eight innings, but said he didn't lobby Maddon to stay in the game.

"I told Joe I was fine, but I also told him that he's the manager," he said. "I've tried before with him, and I think I've won maybe one in the last two years. When he shakes my hand, I know it's one of those deals where it's pretty much done, so there's no real point in arguing."

Grimm allowed singles to pinch hitter Andres Blanco and Cesar Hernandez to start the ninth, and Galvis then drove a pitch deep into the seats in right field, his sixth homer of the season.

Joseph, a rookie first baseman, followed with a blast to deep center, his fifth homer in 19 games with the Phillies.

Rondon, who earned his 11th save, retired the next two hitters but allowed a single to pinch hitter Odubel Herrera. Howard then grounded out to end the game, as the Phillies fell for the ninth time in 11 games.

"That was like two different games," Philadelphia manager Pete Mackanin said. "Good to see the guys fight back."

Philadelphia starter Adam Morgan (1-5) saw his personal losing streak reach five, as he went six innings and allowed three runs and eight hits while striking out five. He didn't walk a batter.

"I was making mistakes in the first inning," he said. "After that, I knew what I was doing wrong."

Fowler led off the game with a double, the 26th time he has reached base to start a game this season, most in the major leagues. One out later, he came around on a ground-rule double by Bryant.

The Cubs made it 3-0 on Heyward's two-run homer in the fourth. Lester doubled with one out, just his second hit in 23 at-bats this season and his sixth in 121 trips during his 11-year career. One out later, Heyward lined Morgan's 2-1 slider into the seats in right field for his third homer of the season.

Chicago added two more runs off reliever Elvis Araujo in the seventh, on Rizzo's RBI single and Javier Baez's safety squeeze. That made it 5-0.

Rizzo delivered another run with a ninth-inning single off reliever Brett Oberholtzer.

NOTES: Cubs LF Jorge Soler left the game after injuring his left hamstring while running out a third-inning single. He was replaced by Matt Szczur. Soler will undergo an MRI on Tuesday, but he didn't believe the injury was serious. ... Philadelphia SS Freddy Galvis ended an 0-for-22 skid with his ninth-inning homer. ... Phillies OF Odubel Herrera, the team's leading hitter with a .317 average, was not in the starting lineup Monday. Philadelphia manager Pete Mackanin said the left-handed-hitting Herrera was in need of a day off, and it was the right time to do it, given the fact that the Cubs started LHP Jon Lester. Peter Bourjos started in center field. ... According to Elias Sports Bureau, Chicago RHP Jake Arrieta became the fifth pitcher (and first Cub) since 1900 to strike out 12 or more in five innings or fewer since 1900 when he fanned 12 over five innings in Sunday's loss to Arizona. That loss snapped a personal 20-game winning streak by Arrieta, dating back to last July 25.