STOCKTON — Senior grad night and the always-pesky Kimball softball team almost got the better of Sierra in Friday’s Sac-Joaquin Section Division IV semifinal at Arnaiz Stadium.

Senior starters Iyana Hughes, Gabby Olmo, Katelynn Perkins and Sommer Wilson were at Magic Mountain in the wee hours, and at times it showed in their play.

Still, the Timberwolves were outplaying their Valley Oak League rival, but three errors led to three unearned runs and a 3-3 ballgame going into the bottom of the sixth. A loss would require them to play again Friday night in the consolation semifinal.

“After grad night that was the last thing I wanted, so after Katelynn got on I knew I had to get her in,” Hughes said.

Perkins led off Sierra’s half of the sixth with a double, and with one out Hughes legged out her own double while driving in the game-winning run of a 4-3 victory.

“Katelynn, after having two at-bats that weren’t that great, got the job done her third time up and put us in position to get that score,” Sierra coach Nick Olmo said. “That was huge, probably the biggest hit of the game right there.”

The win sends the Timberwolves (24-2) into the final round for the third straight year, and for a third straight year the Division IV crown is guaranteed to go to a VOL team. That’s because Kimball (24-7) beat Cosumnes Oaks (17-13) 7-3 in Friday’s semifinal nightcap. Oakdale captured the 2012 blue banner at the expense of Sierra, which earned its first section title in 2011.

Sierra and Kimball will square off at 11 a.m. If Kimball wins, they’ll do it again at 1 p.m. to decide the champion.

The Timberwolves are now 8-1 against the third-year Jaguars, but none of those wins came easily. Expect another doozy, or two, today.

“They’re a good hitting team, they can field and their pitcher does a good job of keeping hitters off balance. Our games are always like this, and I don’t expect that to change in the future,” Olmo said.

With junior hurler Allie Walljasper on top of her game, Friday’s contest could have went more smoothly. Offensively, Sierra had base runners in every inning but the first and stranded 10 of them.

Walljasper registered 14 strikeouts and no walks in a three-hit masterpiece against a team that has had success in hitting her in the past.

“I just came in here more focused on every pitch,” Walljasper said. “We needed to get this one because I don’t think I could have pitched anymore today.”

The LSU commit was perfect through three innings until Kimball’s Llesenia Torres led off the fourth with a single. An error put runners in scoring position with no out. Walljasper limited the damage with two strikeouts, but Kimball was able to plate its first unearned run with Anisha Richardson’s sacrifice fly to left. That cut Sierra’s early lead in half, 2-1.

Walljasper again wiggled out of trouble in the sixth. Danielle Lallos closed Kimball in with a run-scoring infield hit, and Torres plated the tying run on the second of two Sierra errors in the inning. Runners were on second and third, but they were left stranded as Walljasper came through with two clutch strikeouts.

“I didn’t want them going ahead,” Walljasper said. “I knew that if we could get out of it with a tied ballgame that our hitters would come back and get that run.”

Sierra’s other two NCAA Division I prospects also came up big. UC Riverside-bound Wilson went 2 for 4 with two RBIs. Virginia signee Hughes also finished 2 for 4. Walljasper helped her cause with an RBI knock in the third. She drew walks in her next two plate appearances. Freshman Devi Coglio added two runs in a 2-for-3 effort.

“Phenomenal day,” Olmo said of his Big Three. “They did what we expect from them. These girls had about an hour’s worth of sleep, so they’re a little dinged out right now. I’m sure they’ll come out 100 percent (today) and we’ll be all good.”