Bret Hemphill hit a three-run homer in the top of the 11th to cap a four-run Storm rally.
Rafael Novoa (2-2) got the win for the Storm, while Tom Szimanski (1-2) took the loss.
Lake Elsinore (18-13) watched the JetHawks (19-14) tie the game at eight in the bottom of the 10th on Shane Monahan's two-run homer.
Before that, Lake Elsinore's Ty Bilderback broke a 6-6 tie with a two-run double.
Ty Van Burkleo also hit a pair of homers for the Storm in front of a paid attendance of 3,272.
The JetHawks tied the game at six in the bottom of the ninth when, with one out, Marcus Sturdivant scored from second on an infield single by Jason Cook.
The next batter, Scot Sealy, then hit a single to left, but Cook was thrown out at third to send the game into the 10th.
The JetHawks trailed 6-4 entering the eighth, and Sealy led off with a double to left-center and scored on Carlos Villalobos' triple over center fielder Bilderback's head.
But the next three Jethawks - Shawn Buhner, pinch-hitter Monahan and Andy Augustine - struck out, the latter two against reliever Anthony Chavez.
Lancaster reliever Todd Niemeier set down the Storm in the ninth, to keep the JetHawks within one run.
After a sketchy first in which he gave up an RBI single to Sealy, Storm starter Matt Perisho settled down.
Perisho, a left-hander, retired 10 straight before Buhner led off the fifth with a home run to straight-away center field that cut the Storm lead to 4-2.
Perisho, who gave up five earned runs and 11 hits to Lancaster on April 25 in Lake Elsinore, gave up three runs, two earned, and struck out six in six innings.
His replacement, Bryan Harris, wasn't as effective.
Another left-hander, Harris came on in the seventh and promptly walked Augustine to lead off the inning. Luis Molina bunted back to Harris, who threw wildly into center field in an attempt to start a double play at second.
Augustine went to third and scored on Sturdivant's grounder, to tie the game at four.
Van Burkleo and Tony Moeder hit back-to-back homers as the Storm took a 3-0 lead against JetHawks starter Ken Cloude in the first.
Like Perisho, though, Cloude came back strong over the next few innings. After Paul Failla walked in the second and was thrown out trying to steal second as Juan Henderson struck out, Cloude set down the next nine in a row.
But Phillip Dauphin hit a two-out solo homer off the roof of the maintenance building in right field to end Cloude's streak and push the Storm out to a 4-1 lead.
After he gave up 10 runs in three innings against San Bernardino in his last start, Cloude went six against the Storm, gave up four runs on five hits and struck out six.
After the JetHawks tied the game in the seventh, the Storm took a 6-4 lead on Van Burkleo's second homer of the game that also scored Joe Urso.