Francisco Liriano pitched seven strong innings and Pedro Alvarez clubbed a three-run homer in the opening frame, and the Pittsburgh Pirates routed the St. Louis Cardinals, 9-2, in the opener of a pivotal five-game series from PNC Park.
The Pirates, who started an 11-game homestand, played the Cardinals for the first time since a three-game set April 26-28. Pittsburgh took two of three games and left St. Louis in first place in the National League Central.
Pittsburgh, now 20 games over .500, is within a half-game of the Cardinals. The Pirates can move into first place Tuesday with a sweep of a doubleheader. One of those contests is from a rainout on April 16.
Liriano (11-4) allowed a run on four hits and had eight strikeouts. The lefty won for the sixth time in his last seven decisions and moved to 6-1 at home this season.
"He continues to pitch well, be very aggressive and have confidence on the mound," Pirates manager Clint Hurdle said. "The changeup and slider continue to come into play. He's just been very solid, very professional."
Clint Barmes stroked a two-run double to highlight a five-run seventh inning for the Pirates, who entered this series with losses in three of their previous four games.
Jake Westbrook (7-5) was charged with four hits and four runs over five innings to fall to 1-8 in his career against the Pirates.
"He just didn't have a feel at all for his fastball," Cardinals manager Mike Matheny said. "He tried to get a hold of his location and it took him awhile. It took a lot for him to get through five (innings), but the damage had been done already."
Matt Carpenter and Shane Robinson each drove in a run for the Cardinals, losers of four in a row for the first time since Aug. 28-31 last year.
Jose Tabata walked and Neil Walker was hit by a pitch to start the bottom of the first. Andrew McCutchen then lined an RBI single to center. Alvarez clubbed the ensuing pitch over the wall in right for his NL-leading 27th homer and a 4-0 cushion.
Liriano retired the first 10 batters he faced until Carlos Beltran and Matt Holliday had back-to-back singles with one out in the fourth. Liriano then struck out Allen Craig and Yadier Molina.
Pinch-hitter Tony Cruz tripled to center in the sixth and scored on Carpenter's bloop single up the middle.
Liriano escaped a jam in the seventh. After issuing back-to-back, two-out walks to Freese and Robinson, he retired Pete Kozma on a fly ball to center.
The Pirates made it a blowout in the bottom portion. Marc Rzepczynski got into trouble by walking Walker and giving up a single to McCutchen. The runners advanced on a groundout, and Fernando Salas intentionally walked Russell Martin before Gaby Sanchez lifted a sacrifice fly to right field.
Alex Presley then grounded a single through the right side for a 6-1 lead and Barmes followed with a hit to the gap in left-center. Pinch-hitter Starling Marte capped the rally with a grounder into center field to score Barmes.
"We just continue to remind these guys to look in front and play forward, don't look behind. We were able to go out and answer the bell," Hurdle said. "Two big innings tonight, stringing good at-bats together."
Vic Black, in his second major league appearance, gave up a bases-loaded, RBI single to Robinson in the ninth. He retired the next two batters to close the contest.
The Pirates placed catcher Michael McKenry on the 15-day disabled list with a left knee sprain ... This series marks just the second five-game series in PNC Park history. The only other one came in 2001 against the Astros ... Craig is in an 0-for-18 slump ... Liriano is the first Pirates pitcher to win 11 of his first 15 starts in a single season since Dock Ellis in 1971.