The win, combined with the Giants' loss to the Reds, extended San Diego's lead over San Francisco in the National League West to a season-high 6 1/2 games. It also puts the Padres 27 games over .500 for the first time this season, and the first time since 1998.
Eckstein led off the first, third and fourth innings with singles and would come around to score each time. Tejada added two hits, and both players drew a walk.
And the duo was rewarded for getting on base, showing just another example of how the improved Padres offense has helped the team win 13 of their past 16 games to take control of the division in the past two weeks.
In most ways, these are still the same Padres from the first four months of the season. They still have the best pitching staff in baseball, they still run the bases aggressively and they still play outstanding defense.
But the acquisitions of Ryan Ludwick and Tejada have added that extra dose of firepower, and the impact has trickled down to the rest of the San Diego hitters. The Padres are averaging 5.1 runs since Ludwick and Tejada were inserted in the starting lineup, compared to a 4.4 season mark.
"The names have changed, but we're still going to play our game overall with the players we have," Padres manager Bud Black said. "It's nice to add a little power to the lineup."
Tejada provided his own power when he sent a towering two-run homer into the bullpen in left-center, and both he and Eckstein crossed the plate in the third when they started a four-run third inning with a single and walk.
"It was great to see Miggy jump on [D-backs starter Joe Saunders] early and send it to one of the hardest places to hit a homer," Black said.
Eckstein and Tejada would score for a third time when Adrian Gonzalez put the final touch on the night's offensive outburst with a three-run blast to right field in the fourth inning to give the Padres a 9-2 advantage. It was Gonzalez's 156th homer with San Diego, which ties him with Phil Nevin for second on the team's all-time list.
The Padres (76-49) blew the contest open in the third when they sent all nine men to the plate and scored four runs with the help of two errors.
The first miscue came when Stephen Drew bobbled a ground ball off the bat of Chase Headley, allowing Eckstein to score. Rusty Ryal was then charged with a throwing error on a sac fly by Jerry Hairston Jr. that allowed Ludwick and Headley to advance to second and third base. Yorvit Torrealba drove both home when he dropped a single into center field to extend San Diego's lead to 6-1.
"We've done a good job when we're given something to take full advantage of it," Eckstein said. "Chase hit that ball hard up the middle, and it was a tough one, but luckily we were able to score off of that and get a couple more after that. It's one of those things that when you have an opportunity to score, especially against a team like Arizona, you have to take those opportunities."
Wade LeBlanc (8-11) could not retire Drew, who sent two solo shots to right field to record his first career multi-homer game and also added two doubles. But LeBlanc was effective against the rest of the order. In all, he gave up seven hits in 6 2/3 innings and fanned seven to tie his second-highest strikeout total of the season.
"I tip my cap to him," LeBlanc said of Drew. "He got four mistakes, and he didn't miss any of them. Four mistakes too many for a guy like me."
Drew's first long ball, which led off the game, was originally ruled a double, but video replay helped overturn the decision and award Drew the home run.
D-backs starter Joe Saunders (1-4) allowed nine runs (six earned) on eight hits over four innings. He struck out one and walked three.
"It's embarrassing to go out there and give up that many runs," Saunders said. "Hats off to them, they're a good ballclub, but the way I've been pitching I'm making them look like Babe Ruth up there. I've just got to make adjustments."
The victory improved the Padres' record against the D-backs at home this season to 8-0.