CARSON, Calif. -- Sometimes the things you don't know can hurt you.

When Cal State Dominguez Hills head coach Jim Maier intentionally walked Hannah Williams in the bottom of the fifth in a one-run game, he likely had no idea he was loading the bases for the Humboldt State hitter with the highest batting average with the bases loaded: Julie Pena.

Pena smacked the ball over the left field fence for her second grand slam of the year and her eighth hit in 10 at-bats with the bases loaded this season. The Jacks held on for an 8-5 win against the Toros in the first game of the super regional on Friday. It was the ninth grand slam of the year for HSU and homer No. 109, three shy of the NCAA single-season record.

The two teams will play again on Saturday in the best of three series. Winning on Friday, according to HSU head coach Frank Cheek, was bigger than big.

“It's the world,” Cheek said. “Now we only have to win one out of two. Our mindset never changes no matter who we are playing. We play like the other team is the national champions.”

Humboldt (51-12) has won 15 in a row and has won six of seven against the Toros this season. Dominguez Hills dropped to 37-23 overall.

Chrissy Stalf got the Jacks on the scoreboard with a solo home run in the first. It was her 27th of the year. She leads the nation in homers and is one shy of the NCAA record for home runs in a season.

Toros starter Stephanie Jimenez set down nine in a row after Stalf's homer helped her own cause with a two-out double in the fifth to knock in two runs. Jimenez then scored on a hit by Brittany Brenner to give Dominguez Hills a 3-1 lead.

Jimenez almost got out of trouble in the bottom of the fifth after a leadoff pinch-hit single by Sarah Fox, then a two-out walk to Stalf. Tonya Walker, the next batter, hit a flare to right field that dropped in front of three fielders for an RBI single.

“Some hits are hard, and some hits are fate,” Walker said. “Mine obviously was fate because it found a hole between short and second and center field. And it got our team pumped up. And our big hitters did what they normally do. We caught up to [Jimenez] and hit the ball hard.”

Dani Randall was the first of the hard hitters, stroking a line drive to the gap in right center to score both Stalf and Walker to give the Jacks a 4-3 lead. Courtney Hiatt doubled Randall to third, leaving first base open with Williams coming up.

“Jimenez missed a couple times and a couple balls fell in on her,” Cheek said. “And they walked Williams to set the table for Pena. We have Pena there for a purpose. She can hit the long ball, too. That's not the first grand slam she has hit this year.”

Maier replaced Jimenez on the mound after Pena's home run, her 11th of the season. Pena made an over the shoulder catch in foul territory in the seventh to end the game.

“We just shake it off really well,” Walker said. “We have gotten to the point where we are able to shake it off and move on. Like when they up on us, we came back.”

Things did look a bit grim briefly for HSU because Jimenez was powering through the Jacks lineup, giving up just two hits while striking out six in the first four innings. She has a 1.21 ERA against opponents other than Humboldt, and the eight earned runs scored on Friday boost her ERA to 4.38 against HSU. She is 1-4 against HSU and dropped to 26-11 overall.

Adriana Sanchez, who the Jacks were not able to get out on Friday, got a two-run homer in the sixth off Lizzie Perez, who got the win in relief to improve her record to 21-5. Sanchez is 5-for-6 in the last two games against Humboldt, with two home runs, and was on deck when the last out was made by Catherine Brown.