Presley led off the bottom of the first with a drive off the top of the center field fence, the ball just eluding a leaping center fielder Skip Schumaker. It was just the Pirates' second inside-the-parker at PNC Park since it opened in 2001.
Filling in nicely for injured ace Chris Carpenter, Lynn (3-0) gave up four hits. He walked one and struck out four. He has won each of his starts this season and compiled a 1.42 ERA while Carpenter has been on the disabled list with a nerve problem in his pitching shoulder. Lynn pitched primarily in relief last season as a rookie when St. Louis won the World Series.
Daniel Descalso homered for the NL Central-leading Cardinals, who won for the fifth time in six games.
Morton allowed two runs - one earned - and four hits in five innings with three walks and six strikeouts.
After St. Louis tied it in the second inning on Yadier Molina's RBI double, Lynn led off the fifth with a single. He took second on Rafael Furcal's groundout, advanced to third on Matt Holliday's fielder's choice and scored on Beltran's line hit to right field.
Descalso homered - a liner into the right-field stands - in the eighth off Jared Hughes to start a two-run inning. Furcal added a run-scoring double.
St. Louis had tied the game in the second when Yadier Molina's double down the left field line scored Beltran, who reached first on Morton's fielding error.
Presley opened the scoring by scampering around the bases when his drive eluded Schumaker. Jack Wilson hit the Pirates' only other inside-the-park home run at PNC Park on July 2, 2004, and last Pittsburgh player to hit one was Freddy Sanchez at Houston on July 21, 2008.
Schumaker had the wind knocked out of him on the play and left the game. He had been activated from the disabled list prior to the game after missing the first 13 games because of a strained right oblique.
NOTES: Schumaker was activated and 1B Lance Berkman was placed on the 15-day DL with a strained left calf. Schumaker's rehab assignment at Triple-A Memphis was cut short after four games because the Cardinals needed someone to fill in for CF Jon Jay, who sprained his right shoulder on Thursday and is day to day. Schumaker was 3 for 13 (.231) with two walks and two strikeouts at Memphis. . Pittsburgh RHP Jeff Karstens, who was removed from his start after one inning Tuesday and placed on the DL, will rest seven to 10 days before beginning a throwing program. The Pirates do not have a timetable for Karstens' return. RHP Brad Lincoln is expected to start in Karstens' place Monday night against Colorado. . Jake Westbrook (2-0, 0.64) will start for St. Louis against Kevin Correia (1-0, 1.50) on Saturday night. Westbrook is 0-3 with a 5.46 ERA in four career starts against the Pirates.
Link to boxscore: St. Louis 4 at Pittsburgh 1