Gutierrez got hold of the Hastings pitch and hit a home run, giving the Bulldogs a 2-1 lead.
Hastings, who appeared shaken up after giving up the home run, then walked Matt Sauceda before the Imperial coaching staff sent in Bryan Seeger to relieve him and finish the game.
Against Seeger, Hector Rivera landed on base due to a Tiger error and Lopez followed with a walk to load the bases.
Chris Wong then made it to first on a fielder's choice that threw Sauceda out at home to grab the first out.
Seeger then faced Juan Lopez and Damian Lopez with bases loaded but saved the day for the Tigers by striking each out to end the inning.
In the sixth, Imperial looked to tie or even take the lead as it managed to load the bases by walks. But with two outs and bases loaded, Lopez struck out Brenden Lopez and avoided the scare.
Seeger gave up two more hits in the seventh to Rivera and Diego Lopez before Wong batted in Rivera with a single that gave Calexico a 3-1 advantage.
The top of the inning ended on a ground-out.
With the game on the line, Diego Lopez began the bottom of the seventh with five consecutive strikes, striking out Dillon Foster and getting ahead 0-2 in the strike count against Brett Cochran.
Cochran, however, found his way to first, thanks to an error.
Stewart Harvey struck out for the second out and Ray Roben walked to put the tying run on first base.
Then, Hastings stepped to the plate with a tense feeling from both sides of the crowd.
With a 2-2 count, Hastings fouled off a few balls, and then took the final strike to seal the victory for the Bulldogs.
Calexico coach Sergio Rubio said he admired the way Imperial played and forced such a close match-up.
"Hats off to Imperial," Rubio said. "They battled with us for seven innings."
Rubio then complimented the pitching of Diego Lopez.
"I can't say enough about how he's (Lopez) helped the team and he's helped carry us to where we're at today," Rubio said.
Although the Bulldogs are one win away from clinching the IVL title, Rubio said he is not looking past anyone.
"One game at a time. That's what it's all about," Rubio said.
Imperial coach William Estes said he wasn't disappointed by the narrow defeat.
"Both sides played hard," Estes said. "I was impressed with our kids. These guys (Calexico) are undefeated for a reason."
He said he plans to compete successfully in the CIF-SDS playoffs and he said that the Tigers' previous loss to Calexico allowed them to play better baseball.
"We've been playing great ball ever since our last loss to Calexico," Estes said.
Calexico will next travel to Holtville at 4:15 p.m. Tuesday and Imperial will host Central Union High at 6 p.m. Tuesday.
Southwest 21, Holtville 5
The Southwest High baseball team shredded Holtville High 21-5 in five innings in Imperial Valley League action at Freeway Park in El Centro on Friday.
Southwest used a 19-run second inning to open up the lead. George Rapp led the inning with a grand slam.
Alex Caldera finished with two hits, three runs and three RBIs for the Eagles and Paul Rubio and Eric Flores both added two RBIs for Southwest.
Frank Richards picked up the win, pitching five innings with two strikeouts and no walks.
Holtville plays at Calexico at 4:15 p.m. Tuesday and Southwest will host Palo Verde at 4:15 p.m. Friday.
Central 2, Palo Verde 1
BLYTHE — The Central Union High School baseball team narrowly defeated Palo Verde High 2-1 in Imperial Valley League action here Friday.
Leading Central offensively were Victor Cesena, who went 3-for-3 with a run and an RBI double and Raul Cazares, who went 2-for-3.
Jose Ibarra picked up the win on the mound and Humberto Cardenas earned the save.
Central (4-4 IVL) plays at Imperial at 6 p.m. Tuesday.
Mountain Empire 7, Calipatria 1
CALIPATRIA — The Calipatria High baseball team fell 7-1 to Mountain Empire in Citrus League play here Friday.
Losing pitcher was Andy Peralta, who pitched seven innings and scattered nine hits.
Eriberto Perez led the Hornet offense, going 1-for-3.
Calipatria will host Lutheran High at 4:30 p.m. Tuesday.