ST. LOUIS -- In a game they absolutely needed, the Pittsburgh Pirates won with two big innings.

Scoring seven runs in the first inning and three more in the ninth, Pittsburgh avoided a sweep at the St. Louis Cardinals' hands with a 10-5 victory Thursday night.

Francisco Liriano (8-6) struggled through six innings to pick up the win, yielding six hits and three runs, walking four and striking out five. In cutting St. Louis' National League Central lead to six games, the Pirates (66-46) snapped an eight-game losing streak in Busch Stadium, dating back to July 10, 2014.

Starter Lance Lynn (9-7) didn't make it out of the first inning for the first time in 119 career starts for the Cardinals (73-41). St. Louis fell to 42-17 at home and lost for just the eighth time in 25 games since the All-Star break.

St. Louis cut a seven-run deficit to 7-5 in the seventh on an RBI single by shortstop Jhonny Peralta and a sacrifice fly by catcher Yadier Molina, who knocked in three runs.

But Pittsburgh put it away in the ninth. Second baseman Neil Walker drilled a run-scoring double, followed by a run-producing double-play ball from third baseman Jung Ho Kang and a pinch-hit RBI single by Aramis Ramirez.

Aided by unusually shoddy St. Louis defense, Pittsburgh battered Lynn for six hits and seven runs in the top of the first inning, knocking him out after a two-out RBI single by right fielder Gregory Polanco made it 6-0.

First baseman Pedro Alvarez cracked a two-run homer, his 17th home run of the year, a 433-foot blast to center field. Second baseman Neil Walker started the outburst with a triple and ended it with a first-pitch RBI single off reliever Tyler Lyons.

Four of the seven runs were unearned, thanks to a two-base throwing error by third baseman Matt Carpenter. The Cardinals also misjudged two fly balls, with center fielder Peter Bourjos getting turned around twice on Walker's triple and right fielder Jason Heyward losing left fielder Travis Ishikawa's ball in the sun for a single.

St. Louis got two runs back in its half of the first on a bases-loaded single by catcher Yadier Molina, scoring Carpenter and left fielder Randal Grichuk.

NOTES: Pittsburgh LF Starling Marte (left hand) didn't start Thursday night. Travis Ishikawa replaced him in the lineup and batted seventh. Marte left Wednesday night's game after the top of the third inning, complaining of discomfort. ... St. Louis C Yadier Molina's steal of third in the eighth inning on Wednesday night was just the 43rd of his career but his 10th in 13 attempts at third. ... The Cardinals entered Thursday night at 33 games above .500, the first time they've been to that point since 2005.