ST. LOUIS -- For 5 1/2 innings Sunday night, it looked like more of the same for the St. Louis Cardinals.

Mistake pitches, untimely errors and not enough offense against a 2-6 starter put them in a two-run hole and in danger of being swept at home by the Pittsburgh Pirates for the first time in 20 years.

However, Randal Grichuk provided a monstrous power surge, Trevor Rosenthal threw three big pitches to extinguish a seventh-inning rally, and Pittsburgh offered plenty of help in the Cardinals' half of the seventh.

It all added up to an 8-4 St. Louis win that snapped a three-game losing streak and capped a day in which the Cardinals churned nearly a quarter of their roster, mostly because of injury-related moves.

"We take it however we can get it," St. Louis manager Mike Matheny said. "We had good situational hitting tonight, and we stacked hits together."

That was particularly true in the sixth and seventh innings, when the Cardinals (34-40) erased their deficit against Chad Kuhl and three relievers who couldn't get the big outs to keep the game within reach.

Grichuk, recalled from recalled Triple-A Memphis before the game, led off the sixth with the second-longest homer in Busch Stadium III history, a 478-foot rocket that landed halfway up the third deck in left field. His fifth homer of the year sliced Pittsburgh's lead to 4-3.

Kuhl left after Yadier Molina doubled to left-center. Tony Watson got two quick outs, but pinch hitter Jedd Gyorko laced a ground-rule double to right-center that tied the score.

The Pirates (35-41) pushed the tiebreaking run to third with two outs in the seventh. Elias Diaz singled and moved around the bases on two infield outs.

Matheny hooked Matt Bowman and went with Rosenthal to face Josh Harrison, who was 3-for-4 against Bowman but 0-for-8 when facing Rosenthal. Three blazing fastballs later, Harrison was 0-for-9 and the game remained tied.

"We had a short sample with Bowman and a little bit more with Rosenthal," Matheny said of the move. "To me, that was a big moment in that game."

In contrast to Rosenthal (2-3), whose roughly 90 seconds of work earned him a win, Pittsburgh relievers Juan Nicasio (1-4) and Jhan Marinez made a mess out of the inning's bottom half.

Nicasio walked Tommy Pham and Stephen Piscotty to start the inning. After Grichuk fanned, Molina, who wasn't in the original lineup but was inserted into an amended one about two hours before first pitch, poked a tiebreaking single into right for his third hit of the night.

Shortstop Jordy Mercer booted Aledmys Diaz's grounder to score Piscotty for a 6-4 lead. Marinez relieved Nicasio, wild-pitched the runners to second and third, then coughed up a two-run single to Paul DeJong past a drawn-in Mercer.

"We weren't able to make pitches," Pirates manager Clint Hurdle said. "We weren't able to execute the fastball for the most part or the slider. Just too many pitches when you get up to 30 pitches, and the two walks painted (Nicasio) in a bad corner."

The game's one remaining moment of suspense occurred two batters after DeJong's hit. St. Louis-area native Luke Voit, one of three call-ups from Memphis, made his major league debut as a pinch hitter.

With most of the audience of 43,719 chanting his first name, Voit ran the count full and then was drilled by a 96 mph fastball in the back. As he jogged to first, a national TV audience saw his parents pump their fists in the air in joy.

"I didn't feel it," a grinning Voit said. "Honestly, I was smiling going down to first base."

Kuhl permitted eight hits and four runs in five-plus innings, walking one and fanning six. Cardinals starter Mike Leake also got a no-decision after going six innings and giving up six hits and four runs, three of them earned. He walked two and struck out two.

Adam Frazier lined a two-run triple in a three-run third for Pittsburgh, which finished a seven-game road trip at 4-3.

NOTES: St. Louis CF Dexter Fowler (right heel spur) and LHP Kevin Siegrist (cervical spine strain) each landed on the 10-day disabled list Sunday. 1B Luke Voit and RHP Mike Mayers were called up from Triple-A Memphis. The Cardinals also optioned OF Chad Huffman to Memphis. ... Pittsburgh 2B Josh Harrison was hit by a pitch Saturday, the major-league-leading 16th time he took first base with a bruise for his trouble. He has been hit five times in the last seven games.