Piscotty reached base three times, drove in a run and played mistake-free at first base. He did plenty right, though it wasn't enough as St. Louis fell short against the Atlanta Braves 3-2 on Sunday.
Atlanta used seven strong innings from rookie right-hander Matt Wisler and a tiebreaking homer in the seventh from rookie third baseman Adonis Garcia to avoid a three-game sweep against the team with the majors' best record.
Piscotty had been set to make his first start at home on Thursday but was a late scratch because of a stiff neck he said he suffered while sleeping.
Given his chance a few days later, the 24-year-old out of Stanford showed why he entered the season as the Cardinals' top prospect. He singled in the Cardinals' first run in the fourth inning, led off the sixth with an infield single and walked in the eighth.
''The reason Stephen's been able to move through the system and be at the top of our prospect list is the mature at-bats he takes,'' Cardinals manager Mike Matheny said. ''He's a guy that's disciplined inside the zone, doesn't chase a lot out. He has a very consistent approach and swing. Today was a good day.''
Piscotty also kept the Braves from scoring in the eighth when he made a stretch at first on a throw from Matt Carpenter with two out and a runner on third.
''There's a lot of stuff to work on is but I feel comfortable and today was a good first step,'' Piscotty said. ''It was good to get the experience and I'm pretty happy about how it went.''
Cardinals starter Michael Wacha (11-4), who had allowed five earned runs in each of his previous two starts, gave up five hits and walked three in six innings. The Braves took a 2-0 lead in the second when Wacha walked two, gave up a run-scoring double to Ryan Lavarnway and a two-out single to Cameron Maybin on an 0-2 changeup. He needed 51 pitches to get through the first two innings.
''I have to do a better job with those counts and being able to put them away,'' Wacha said. ''I felt like I got stronger as the game progressed.''
Piscotty's single to left that scored Jason Heyward gave the Cardinals their first run but not without a lengthy delay. Heyward, scoring for the first time against his former team, initially was ruled out but the call was overturned following a 5-minute, 8-second review that showed he slid in ahead of Lavarnway's tag.
Garcia, a 30-year-old released by the Yankees in spring training, led off the Braves' sixth by hitting a 1-0 fastball from Wacha into the right-field bullpen. The homer was Garcia's first in the majors.
''The ball was up in the zone and he put a good swing on it,'' Wacha said. ''I have to get the ball down in hitters' counts.''
Matheny said the ball carried ''uncharacteristically far'' in a park that has yielded the fewest homers in the National League.
Cardinals: CF Randal Grichuk left after the sixth inning with what Matheny called a minor groin injury. Grichuk suffered the injury when he was running the bases after singling in the fourth inning.
Braves: LHP Alex Wood (7-6, 3.78 ERA) will face RHP Kevin Gausman (1-2, 5.18) in the opener of a three-game series as Atlanta continues a three-stop trip. The Braves are not scheduled off until Aug. 10.
This story has been corrected to change to Thursday in 4th paragraph.