PHILADELPHIA (AP) - Jake Arrieta didn't feel on top of his game. He still displayed dominance that has him among the leading NL Cy Young Award candidates.
Arrieta pitched eight strong innings for his major league-leading 19th win, and Starlin Castro homered to lead the Chicago Cubs past the Philadelphia Phillies 5-1 in the first game of a doubleheader Friday night.
The right-hander said his timing was off, but it didn't prohibit him from shutting down the Phillies.
"Sometimes your body reacts differently on certain nights and it's hard to get into that rhythm," he said. "The adjustment necessary to have a quality outing can be made regardless of how you feel."
Arrieta (19-6) won his eighth straight start, allowing six hits with seven strikeouts and two walks to become the first Cubs pitcher to win that many in a row since Milt Pappas won 11 consecutive games in 1972. In his last 16 starts dating to June 21, the right-hander is 13-1 with a 1.00 ERA and 115 strikeouts in 117 innings. He lowered his season ERA to 1.99.
"Nothing fazes me," Arrieta said. "Men on base, walks, homers. . Deal with it and move forward."
While Arrieta deflected questions about possible upcoming milestones, manager Joe Maddon didn't back away from Cy Young talk.
"I definitely believe our guy deserves it, no question," Maddon said. "I've seen (Zack) Greinke pitch. I know he's really good. I'm getting to watch Jake in person; it's pretty spectacular to watch. My vote's for Jake."
Addison Russell hit a two-run double and Kris Bryant set a club rookie record with his 87th RBI for Chicago, which entered play nine games ahead of San Francisco for the second NL wild-card spot. The Cubs have won six of their last seven.
Aaron Altherr homered for Philadelphia, which has lost 13 of 17.
The nightcap was scheduled to start 30 minutes after the opener of the twin bill, which was necessitated by Thursday night's rainout.
The only blemish for Arrieta was Altherr's second-inning solo homer, which halted his streak of consecutive innings without an earned run at 30 2-3.
Adam Morgan (5-6) allowed four runs and seven hits in five-plus innings.
"I got some balls over the plate and they're a good-hitting team," Morgan said.
The Cubs went ahead with two two-out runs in the fifth. Dexter Fowler tied the game at 1 when he scored from first on Austin Jackson's double to left, and Jackson reached on Bryant's double to right.
Philadelphia played its first game since Thursday's firing of general manager Ruben Amaro Jr.
Bryant eclipsed Billy Williams (1961) and Geovany Soto (2008) with the run-scoring hit. His 87 RBIs are tops among rookies in the majors.
"It just shows, when there's people on base he becomes an even better hitter," Maddon said. "You get guys with that mentality, it makes all the difference in the world."
Bryant, who normally plays third base, made his third appearance in left field. Javier Baez started at third.
Castro, who lost his role as an everyday player to 21-year-old shortstop Russell, belted his eighth homer with two outs in the seventh. It was the 13th RBI in 17 games in Philadelphia for Castro, who is 9 for 16 in his last five games overall.
Ryan Howard of the Phillies went 0 for 4 with a strikeout to extend his career-worst slump to 0 for 33. It is the club's longest streak wince Raul Ibanez went 35 straight at-bats without a hit in 2011.
Cubs: C Kyle Schwarber, who has been battling an oblique/rib injury, didn't play.
Phillies: Interim manager Pete Mackanin said 3B Maikel Franco (fractured left wrist) will take live batting practice "in a few days." Mackanin is eyeing Sept. 22 at Miami as a possibility for Franco, who has been on the DL since Aug. 12, to rejoin the club.
RHP Dan Haren (9-9, 3.73) takes the mound for the Cubs on Saturday night against Phillies RHP Jerad Eickhoff (1-3, 4.70).