Pedro Ciriaco hit a tie-breaking triple in the seventh and added a two-run homer an inning later and Padres defenders turned in three defensive gems while the game was on the line Thursday night as the hosts opened a four-game series against the Dodgers at Petco Park with a 6-3 win before 30,056.

The Padres eighth win in their last 10 games – and seventh straight win at Petco Park – moved them back over .500 and past Colorado into third place in the National League West.

Ciriaco tripled home Yasmani Grandal in the bottom of the seventh to break a 2-2 tie and slumping Chase Headley added a two-out, run-scoring single to give the Padres a two-run lead.

Ciriaco, who was acquired in a trade from Boston a week ago, then followed a second straight Grandal hit with his first National League homer to up the Padres lead to four runs.

“Every time I get a chance to be in the lineup, I’m going to play hard and try to make something happen,” said Ciriaco, who is filling in for the injured Everth Cabrera at shortstop.

But as memorable as Ciriaco’s hits were the defensive plays turned in by the Padres in the seventh and eighth while the game was still on the line.

The biggest being a diving catch in right-center by center fielder Alexi Amarista in the top of the eighth that prevented at least one Dodger run from scoring.

An inning earlier, two Padres defenders made two excellent catches. First, second baseman Logan Forsythe raced into short center before making a diving over-the-head catch of a sinking liner by Mark Ellis leading off the inning. Then Chris Denorfia raced across the foul line in left to catch a foul fly by pinch-hitter Elian Herrera as he tumbled over the low rail into the left field stands.

“Those are three really great plays,” said Padres manager Bud Black. “The guys played their butts off on the defensive side.

“(The win) was a collective effort by the group. We really don’t have, yet, that player who can carry the team for a while. A lot of contributors again. That’s how we do it.”

Grandal opened the seventh with an opposite-field double into the left field corner off Dodgers reliever Matt Guerrier. Ciriaco followed with a booming triple to left center.

The Padres added the fourth run after former Padres first baseman Adrian Gonzalez foiled a suicide squeeze attempt by fielding Will Venable’s bunt on the run and glove-flipping the ball to catcher A.J. Ellis for the tag on Ciriaco.

But Headley, who had struck out in each of his first three at-bats to slip under .220, singled to center off Paco Rodriquez to drive home Logan Forsythe.

Ciriaco is 7-for-17 since joining the Padres on June 15. His three RBIs Thursday night were his first as a Padre.

The win also widened the Padres margin over the last-place Dodgers to six games.

Starter Jason Marquis allowed just two runs – the first on a tape-measure homer by Dodgers rookie sensation Yasiel Puig – on seven hits over six innings but failed in his attempt to become only the fifth starting pitcher in Padres history to have a winning streak of nine or more games.