CINCINNATI (AP) — The weekend started badly and ended worse for the Cincinnati Reds, who sense that something is starting to slip away.

Matt Carpenter broke his 0-for-23 slump with a bases-loaded double during the decisive rally, and the St. Louis Cardinals ended a tough trip on the upswing by beating the Reds 15-2 on Sunday, finishing off a rough series for the defending NL Central champions.

“This was disheartening,” reliever Sam LeCure said. “Losing is one thing, but going out there and getting embarrassed in front of your fans who are showing up to support you is another. And we did just that.”

The loss dropped third-place Cincinnati 6 1/2 games behind the Pirates, their biggest deficit since the end of the 2011 season. The Reds are 10 games over .500 and still in good shape for a wild card, but that’s not much comfort.

“We’re running out of tomorrows and we need a sense of urgency,” LeCure said. “We’ll see what we’re made of here coming down the stretch. Thankfully we do have some time to get it right.”

Along the way, they’re going to have to figure out how to beat the Cardinals, who have beat them up pretty regularly this season.

St. Louis took two of three at Great American Ball Park and has won its last six series against Cincinnati, its best such stretch against the Reds since 2003-04. The Cardinals lead the season series 8-4.

They opened the series with a 13-3 win on Friday. On Sunday, they finished it with their most runs against Cincinnati since 1993. They’ve scored at least 10 runs against the Reds in four games this season, the first time they’ve done that since 1980.

It’s been that lopsided.

“Some teams you play better than others, but they’ve got our number for sure,” said Mike Leake (10-5), who gave up a season-high seven runs. “They play us tough. It’s on us to try to figure them out because they’ve got us figured out for the most part.”

Carpenter’s two-run double off the wall completed a five-run rally in the sixth against Leake and two relievers. Matt Adams, David Freese and Tony Cruz homered for the Cardinals, who have scored 13, 13, 3 and 15 runs in their last four games.

St. Louis finished with 19 hits and a season high in runs. Every starter except Lance Lynn drove in at least one run.

“That’s one of the worst defeats I can remember,” manager Dusty Baker said. “We just had another ‘worst’ two days ago, and this one was worse than that. We certainly have to get our act together.

“I don’t like getting beat up. I don’t like getting embarrassed.”

Lynn (13-5) allowed four hits in eight innings, including Zack Cozart’s two-run homer. Lynn struck out a season-high 11 and joined Adam Wainwright as 13-game winners in a rotation that has the NL’s third-best ERA.

The Cardinals scored in the first inning of all three games of the series. They scored four off Bronson Arroyo on Friday night, one on Saturday and four more off Leake, who had allowed a total of four runs in his last three starts combined.

Matt Holliday and Freese had RBI doubles, and Adams hit a two-run homer — his first since July 6 — for the 4-0 lead only 19 pitches into the game. Holliday improved to 9 for 20 career off Leake.

The Cardinals sent 10 batters to the plate for five runs in the sixth, aided by a pair of errors. They opened the inning with five consecutive hits, and Carpenter’s two-run double off Logan Ondrusek made it 9-2.

The Cardinals hit only nine homers in July, including one after the All-Star break. They had six in three days at Great American Ball Park.

Reds third baseman Todd Frazier went without a hit for his ninth straight game, leaving him in an 0-for-28 slump. It’s the longest by a Reds player since Drew Stubbs went 0 for 32 midway through last season.

Notes: The Cardinals play 17 of their next 24 games at Busch Stadium. They open a 10-game homestand on Monday against the Dodgers, with Wainwright trying for his 14th victory. … The Reds are off on Monday before resuming their homestand with a pair of games against the Athletics. … Cardinals OF Carlos Beltran got a day of rest. … Reds LH reliever Sean Marshall and RH starter Johnny Cueto still haven’t resumed throwing. Marshall, on the DL since May 24 with a sore left shoulder, had a setback before the All-Star break. Cueto has been sidelined since June 5 with a strained muscle in the back of his shoulder.

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