The 20-year-old Guerra, who was acquired from Boston in the trade for closer Craig Kimbrel last November, is the second-rated prospect in the Padres farm system.
Third baseman Fernando Perez, a product of Otay Ranch High, also had a run-scoring double for the Storm.
Right-handed starter Dinelson Lamet, 23, allowed two runs on three hits and two walks with four strikeouts in four innings.
Right-hander Chris Huffman allowed a hit with three strikeouts in two scoreless innings to be credited for the win. Left-hander Jose Torres walked one with two strikeouts in a scoreless seventh.
Right-hander Colby Blueberg, 22, who had 21 saves with a 1.07 earned run average in 41 appearances for low Single-A Fort Wayne last season, earned his first save with Lake Elsinore allowing a hit with a strikeout in two innings.
AROUND THE FARM:
TRIPLE-A EL PASO: RENO 8, Chihuahuas (0-1) 0 - Former Major League right-hander Jeremy Guthrie allowed five runs (three earned) on six hits and a walk in three innings in his first Chihuahuas start. Left-hander Frank Garces allowed three runs on three hits and a walk with three walks in 2 1/3 innings. C Austin Hedges was 2-for-4 with a double and an error. CF Manuel Margot had a double in four at-bats with an error.
DOUBLE-A SAN ANTONIO: Springfield 3, Missions (0-1) 1 - SS Jose Rondon was 2-for-4 with a run scored and a steal. Starting RHP Fabio Castillo, 27, allowed three runs on six hits and a walk with six strikeouts in six innings. LHP Ramon Benjamin, 28, allowed two hits and a walk with a strikeout in two scoreless innings.
LOW SINGLE-A FORT WAYNE: LAKE COUNTY 8, TinCaps 7 (10 innings) - Starting right-hander Walker Lockett allowed two hits in five scoreless innings. LHP Taylor Cox allowed three runs (one earned) on four hits with three strikeouts in 2 1/3 innings. RHP Phil Maton allowed a run on three hits and a walk with a strikeout in 1 1/3 innings to suffer the loss. Corner infielder Ty France was 2-for-4 with two homers and two RBIs and had the honor of hitting the first homer in the Padres system in 2016. C Austin Allen was 4-for-5 with a RBI and run scored. 1B Brad Zunica was 3-for-5 with a RBI. LF Rod Boykin had a double and a triple in six at-bats with a RBI.