Maikel Franco fouled off a curveball, battling to keep his at-bat alive in the first inning on Saturday night. It was the seventh pitch of yet another long at-bat, as Franco has started the season with a new, grinding approach. The longer the at-bat, the
more likely the pitcher will make a mistake.

The mistake came on pitch No. 8 — a grooved fastball — and Franco did not miss. He crushed Dillon Peter's offering for a grand slam into the left-field stands, and the rout was on — a 20-1 thrashing of the Miami Marlins at Citizens Bank Park.

The Phillies scored 17 runs in the first four innings and rolled to their second-most lopsided win since at least 1908, according to Baseball Reference. They hit four homers and scorched eight extra-base hits. The Marlins used a catcher — Bryan Holaday — to pitch the eighth.

It was a trouncing, and the first strike came from Franco, who finished with a career-high six runs batted in.

Aaron Altherr added a grand slam in the third — the first time the Phillies rocked a pair of grand slams in the same game since Ryan Howard and Raul Ibanez did it in 2009. Altherr and Franco's slams both came against Peters, who became the first pitcher to serve up two grand slams against the Phillies. Franco, dating to last season, homered in his fifth straight home game and drove in two runs in the fourth with a double.

"I feel pretty good," Franco said. "I'm trying to get more deeper in the counts. Trying to work, not try to hurry or do too much. Just try everything I can do to get better."

A weekend with baseball's worst team might be just what the Phillies needed. They entered the series with two runs in four days and 19 runs in their first six games. They scored 25 runs in the first two games of the series and could complete the sweep on Sunday in Jake Arrieta's debut.

Carlos Santana hit a three-run homer for his 1,000th career hit, and Rhys Hoskins had an RBI double and finished with three RBIs. Jorge Alfaro, who was lauded Thursday for his improvements behind the plate, belted a 433-foot homer to give the Phillies their 20th run.

Vince Velasquez pitched the first six innings, and Jake Thompson handled the final three in relief to earn a save. They combined to hold the Marlins to five hits, with nine strikeouts and one walk. After the game, Thompson was optioned to triple A to make room for Arrieta.

"Twenty runs, that's crazy," Velasquez said.

In spring training, Phillies first-year hitting coach John Mallee restructured Franco's stance, bringing his front foot almost parallel with his back foot. The coach told Franco to use his hips more and stay direct on the ball with a balanced swing. His wide, open stance would often leave him vulnerable. Franco's movements, Mallee told him, should all be lineal with the pitcher. Hit the ball back from where it's coming from, he told Franco. Simple enough.

"During spring training, he hit a lot of hard line drives that ended up getting caught, and in a really short look, one starts to get discouraged. We never got discouraged," manager Gabe Kapler said. "If you really have that patience, that's why we don't look at baseball in a three-, four-, five-game stretch. You look at it over a long period of time to get a good feel for what's actually happening, and some really good things were happening for Mikey. This is not coming as a surprise to anyone in the Phillies clubhouse. We saw this coming."

The new stance has yielded early success. Franco said he feels comfortable. He has 10 RBIs in the last two days. His exit velocity, according to MLB's Statcast data, is 5 mph faster, and his launch angle is improved. And, perhaps most importantly, he looks in control of his at-bats. He has seen an average of 4.5 pitches per plate appearance this season, nearly a half-pitch more than he saw last year. His new approach is working.

It was just the 10th day of the season. Franco could lose his approach and change his stance on the 11th day. But the first 10 days offered promise for a season that is crucial to Franco's future with the Phillies. The team is ready to spend on free agents this winter. Franco must prove he belongs.

He circled the bases after his grand slam, high-fived third-base coach Dusty Wathan, pointed to the sky, and leaped in the air 6 feet in front of home plate. Franco crossed home and leaped again.

A good night for Franco — and for the Phillies — was just getting started.