Nick Pivetta deals, new-look Padres beat the Cardinals

Nick Pivetta allowed just one hit in seven innings and Jackson Merrill capped a four-run fifth inning with a two-run single as the San Diego Padres beat the visiting St. Louis Cardinals 4-1 for their sixth straight win Friday night.

Pivetta (11-3) improved to 7-0 at Petco Park this season, walking none and striking out five as he lowered his earned run average to 2.73. New acquisition Mason Miller pitched a scoreless eighth and MLB saves leader Robert Suarez worked the ninth for his 31st save in 35 chances.

Matthew Liberatore (6-9) matched Pivetta pitch-for-pitch for four innings and even got a 1-0 lead when Willson Contreras cracked his 15th homer of the year to start the top of the fifth. Contreras jumped on a fastball down the middle and launched it an estimated 398 feet to the seats in left-center.

But San Diego took advantage of shaky defense to crack the code in its half of the fifth. After Jake Cronenworth walked with one out, Jose Iglesias' slow roller to third became two errors and a run. Nolan Gorman's wild throw to first was worth two bases and Contreras' inaccurate heave to third cashed Cronenworth in.

Elias Diaz looped an RBI single to left-center for the go-ahead run. Fernando Tatis Jr. worked a walk and Luis Arraez singled to fill the bases. Reliever Matt Svanson fanned Manny Machado but Merrill laced a cutter into center field that scored Diaz and Tatis.

Liberatore was charged with all four runs, one earned, on four hits and two walks in 4 1/3 innings. He fanned one.

St. Louis welcomed Miller to his new team with consecutive singles by Masyn Winn and Nolan Gorman. But Miller whiffed Jordan Walker with a 101 mph fastball and then induced a double play ball off Yohel Pozo's bat.

Ramon Laureano and Ryan O'Hearn, who were also acquired on a busy Thursday by the Padres, debuted on Friday. Laureano played in left field and went 0-for-4, while O'Hearn pinch-hit in the sixth. He was hit by a pitch and lined out in his two plate appearances.