BOSTON – Daniel Nava gave his parents a great home video.

Nava hit the first pitch he saw as a big leaguer for a grand slam — only the second player to do it — leading the Boston Red Sox to their second straight rout of the Philadelphia Phillies, 10-2 Saturday.

Nava connected on a fastball from Joe Blanton in the second inning, shortly after being called up from Triple-A Pawtucket. Kevin Kouzmanoff hit a slam on the first pitch he saw Sept. 2, 2006, for Cleveland against Texas, according to STATS LLC.

With his parents watching from the stands — and his father operating a video camera — Nava came to bat with the Red Sox trailing 2-1.

“It’s funny. They really hadn’t seen me play in the last two years,” he said. “They were in Indianapolis to watch me play on Friday and I told them I might be playing up here.”

His parents overcame a bit of travel trauma to get to Fenway Park in time for their son’s debut. His mom said that when the luggage was slow to arrive at the airport, they left it there and headed straight to the ballpark.

Nava often was regarded as too little to play during his career at all levels. Undrafted out of college, he was the MVP of the independent Golden League in 2007, and signed with Boston.

With his mother and father watching from the back of the postgame interview room, Nava was asked about his climb to this moment.

“It’s ridiculous,” he said.

Only four players in big league history have hit grand slams in their first at-bat. Nava became the 10th player to homer in his first at-bat for the Red Sox, and just the second to hit a grand slam — Rip Repulski did it on May 10, 1960.

Nava’s slam brightened a rainy day that started out poorly for the Red Sox, even before the first pitch.

Daisuke Matsuzaka was a late scratch and was placed on the 15-day disabled list with a strained forearm following his pregame throwing.

“When he was warming he said his forearm was sore,” Manager Terry Francona said. “He said he could pitch, but would have to change his delivery. We weren’t comfortable with that.”

Emergency starter Scott Atchison, recalled from Triple-A Pawtucket on Friday, worked three innings, allowing two runs and two hits in his first major league start.

Batting last in the order, Nava pulled the first pitch he saw into the Boston bullpen in right-center field, where reliever Manny Delcarmen made a leaping catch.

Nava got an enthusiastic greeting in the dugout, with Kevin Youkilis among those pounding him on the batting helmet. Encouraged by his teammates, Nava took a curtain call.

“I knew it was his first at-bat, but I tried to throw him a sinker away,” Blanton said. “I threw it right down the middle and it didn’t sink.”

As luck would have it, Nava came up the next inning with the bases loaded again, but he struck out on a check swing.

Nava later hit a line-drive double into the left-center gap, and finished 2 for 4.

The Red Sox pounded Blanton (1-5) for nine runs and 13 hits in four innings. But, he didn’t fare as badly as Friday’s starter, Jamie Moyer, who had the worst start in his 24 seasons, allowing nine runs and nine hits in one-plus inning.

J.D. Drew homered and had three hits for the Red Sox.

Delcarmen (2-2), the second of five Red Sox pitchers, worked two scoreless innings for the win.