ST. LOUIS -- A close game through 5 1/2 innings turned into a blowout in an instance.
The key hit occurred when pinch-hitter Matt Adams, who was batting for pinch-hitter Michael McKenry after San Diego removed starter Christian Friedrich for Carlos Villanueva, lined a 3-2 pitch up the gap in left-center, scoring Jedd Gyorko and Greg Garcia for a 4-1 lead.
Aledmys Diaz followed with a two-out RBI triple and Stephen Piscotty tacked on a run-scoring single to make it 6-1. Randal Grichuk and Gyorko belted back-to-back homers in the seventh for a 9-2 advantage and Piscotty capped the scoring in the eighth with a 439-foot homer to the third deck in left field.
Mike Leake (7-7) earned the win with six solid innings, fanning a season-high 11 and allowing six hits. He gave up a run and walked none. In his last two starts, Leake has 21 strikeouts and no walks.
Friedrich (4-6) lasted 5 1/3 innings, permitting six hits and four runs, three earned. He issued five walks and struck out two.
St. Louis (48-44) remained two games behind Miami for the National League's second wild-card spot, while the Padres dropped to 41-52 in the opener of a 10-game road trip.
San Diego broke the scoring seal in the top of the fourth when Matt Kemp jumped on a 2-1 sinker that didn't sink enough and launched it 410 feet over the center-field wall for his 19th homer of the year.
Aside from that, Leake baffled the NL's highest-scoring team since June 1 with another surprising batch of strikeouts. After fanning 10 in his last start on July 10 in Milwaukee, Leake whiffed 10 in the first five innings of this one, including three punch outs of All-Star first baseman Wil Myers.
Friedrich kept the Cardinals off the board until the bottom of the fifth. Matt Holliday lined a two-out RBI single to left that scored Leake, who led off with a four-pitch walk, and a throwing error by Alex Dickerson enabled Diaz to score the tiebreaking run.
NOTES: Former St. Louis scouting director Chris Correa was sentenced to 46 months in federal prison Monday for unlawful intrusions into the Houston Astros' database. Correa, who pled guilty to five charges on Jan. 8, must also pay restitution of $279,038.65 to the Astros. ... San Diego CF Melvin Upton, Jr. returned to the lineup after missing three games while on the bereavement list. INF Brett Wallace was placed on the paternity list to make room on the roster. ... Cardinals 3B Jhonny Peralta (left thumb), who left Sunday's game in the fifth inning, was not in the starting lineup Monday.