PHOENIX -- Mark Leiter Jr. was lights out in his first major league start, one that took the former 22nd-round draft pick plenty of years and plenty of setbacks to make despite his major league heritage.

Leiter kept Arizona off-balance by effectively mixing his pitches over six shutout innings in his starting debut, and Maikel Franco and Tommy Joseph homered in the late innings to help the last-place Philadelphia Phillies cool off the Diamondbacks in a 6-1 win on Friday night.

Arizona, coming off a 7-1 road trip, had won nine of 10 overall and 11 of 12 at Chase Field only to generate almost no offense against Leiter (1-0), whose first 12 career appearances came in relief.

"He's always been under the radar, one of those guys that people have always doubted, but his mentality and the way he prepares and gets ready for this, he's second to none," said Joseph, a Leiter teammate in both the majors and minors. "They're one of (the) best offenses in baseball, (but) he kept them off-balance and was in command of the strike zone."

The son of Mark Leiter and the nephew of Al Leiter -- both former major league pitchers -- the 26-year-old Leiter wasn't overpowering, with a fastball that topped out in the low 90s, but he constantly forced the Diamondbacks to chase cut fastballs, change-ups and a dominating split-finger fastball down in the strike zone. It probably made fans wonder why he labored with six minor league teams before finally reaching the majors at age 26.

"He made it look easy, used all of his pitches and pitched ahead all but one inning," Phillies manager Pete Mackanin said. "He had a good changeup he threw behind in the count, the splitter was his go-to pitch and he made a lot of hitters look bad on a good-hitting team."

Leiter couldn't have pitched much better for a team that had won only two of its previous 15 games, striking out five and walking one before giving way to his bullpen after throwing 81 pitches, 51 for strikes.

"It says a lot about what kind of pitcher he is, first major league start and he comes up and does that. It (Chase Field) is known as a hitters' ballpark, and it means he's pretty strong between the ears," Joseph said.

The Phillies, winning successive games for the first time since June 5-6, didn't generate much offense themselves until the final two innings, but they turned Freddy Galvis' one-out triple in the first off starter Patrick Corbin into a run, then added a key insurance run when Franco hit his ninth homer of the season -- a line drive to right field off Jorge De La Rosa on a 3-0 pitch in the eighth.

Galvis' second homer in four games against Arizona this season proved important in the bottom off the inning when Daniel Descalso's first triple of the season scored Rey Fuentes, who began the inning with a single. But reliever Joaquin Benoit recovered to strand Descalso at third, getting David Peralta on a line drive to short and striking out Jake Lamb around a walk to Paul Goldschmidt.

"You're going to have those days," catcher Chris Iannetta said of only the second Diamondbacks loss at home since May 14. "(We'll) brush this one off and come back tomorrow. It's not the end of the world."

Philadelphia, winning its fifth in a row at Chase Field since 2015, broke it open with a four-run ninth against T.J. McFarland that included Joseph's two-run homer into the swimming pool in right field, his 12th of the season.

"There was a lot of good stuff out there," Mackanin said, including Leiter's first major league hit, a single in the second inning.

The Diamondbacks had scored 26 runs in their previous two games, but didn't give Corbin (6-7) any support as he allowed only one run over 6 1/3 innings despite giving up eight hits.

"The first two innings I threw a lot of pitches but then I settled down," Corbin said. "(There were) a lot of ground balls, some that got through, but some that didn't."

Pat Neshek followed Leiter -- whose father was in the stands to see his son's starting debut -- with a scoreless seventh inning, and Hector Neris pitched the ninth in a non-save situation. The Leiters are the 15th father-son combination in major league history to pitch for the same team.

The Diamondbacks, coming off a franchise-best 7-1 road trip to Detroit, Philadelphia and Colorado, had a couple of chances early to get to Leiter, only to have the rookie pitch out of trouble.

The Phillies played without their hottest hitter of late, second baseman Howie Kendrick, who was scratched with left hamstring tightness less than an hour before game time. Kendrick, out more than a month earlier this season with an oblique injury, doubled as a pinch-hitter in the ninth.

NOTES: Phoenix Suns first-round draft pick Josh Jackson and Arizona Cardinals first-round pick Haason Reddick threw out ceremonial first pitches. ... RHP Randall Delgado (1-1) will make a spot start for Arizona on Sunday, in part to give RHP Taijuan Walker some extra rest. ... The D-backs placed RHP J.J. Hoover on the disabled list with right shoulder inflammation and brought up RHP Rubby De La Rosa from Triple-A Reno, where he was 0-1 with a 2.35 ERA with 23 strikeouts in 15 1/3 innings. He was 4-5 for Arizona last season while being limited to 13 appearances by right elbow inflammation. ... A moment of silence was observed for former Arizona State football coach Frank Kush, who died Thursday. ... The Phillies played the second game of a 20-game stretch in which the starting time is different than the day before. ... After the game, the Diamondbacks optioned OF Jeremy Hazelbaker to Triple-A Reno.