It was Blanton's third straight victory and ran his road record to 6-1 over his past 11 starts as the Phils improved to 17-6 on the road this season.
It was a night of double back-to-back jacks as Chase Utley and Ryan Howard hit back-to-back home runs for the Phillies in the fifth off loser Kevin Correia (1-4) before Adrian Gonzalez and Scott Hairston hit back-to-back homers off Blanton in the sixth.
"Those were solo home runs," said Blanton, "and we still had the lead. I had two outs and no one on. I was just being aggressive and two home runs. No need to make another bad pitch after that second home run [by Hairston]. If you make another one, we got a tie game, so I just went back to doing what I did earlier in the game.
"I knew Gonzalez was hot, I just attacked him," said Blanton, "but I just overthrew it and threw a sinker that kind of flattened out. Hot hitter, hang the ball over [and] up a little bit and that's what happens."
The home run by Gonzalez was his Major League-leading 21st homer of the season. Hairston followed with his eighth homer and third in his past three games.
Utley had hit his 12th homer of the season leading off the fifth. It was his fourth against the Padres this season and 10th of his career against them. Howard followed with his 15th of the season as the Phillies took a 4-1 lead.
Utley went 2-for-4 and drove in two runs, his first on an RBI single in the third when Philadelphia scored twice to take a 2-1 lead.
Howard, who struck out four times sandwiched around his 426-foot home run, opted not to talk after the game, saying, "Not this time."
It marked the second time the Phils have hit back-to-back homers this season as Shane Victorino and Utley did the trick in Florida on April 24. It was also only the second time that two teams had back-to-back homers in the same game, as Arizona and Milwaukee accomplished the feat in Milwaukee, with Mark Reynolds and Justin Upton going deep in the seventh for the D-backs after Prince Fielder and Mike Cameron homered for the Brewers in the second.
"Joe Blanton is a guy who is big and strong and very durable," said Manuel. "Command plays a big role. He can move his fast ball in and out and up and down and when he's getting his slider and curveball and locate those balls he becomes a pretty consistent pitcher."
"I feel a little more comfortable with runners on, especially my changeups," said Blanton. "I'm not putting more pressure on myself, I have good slot in my release and I'm just trying to pound the strike zone and when that happens a lot more things are working."
The Phillies did have a little drama in the ninth after tacking on an insurance run in the eight on a pair of doubles by pinch-hitter Greg Dobbs and Victorino off Padres reliever Luke Gregerson.
Left-hander Scott Eyre, who pitched a perfect eighth, walked Adrian Gonzalez leading off the ninth. Brad Lidge came on and got Hairston on a fly to left. With Brian Giles up, a pitch got away from catcher Carlos Ruiz. Gonzalez took off for second. He slid in safely, but his foot came off the bag and shortstop Jimmy Rollins tagged him out.
Padres manager Bud Black and Gonzalez argued with umpire Paul Emmell, but to no avail.
"[Gonzalez] was sliding hard to make sure he got to the bag," said Rollins. "He kind of went past the bag. My job is to apply a firm tag and in doing so with his momentum carrying him beyond the bag. His foot and leg were at full extension. And ... a good tag will usually help you a little bit."