Buffalo Grove just doesn't worry.
Even when the 17th-seeded Bison were trailing top-seeded Mundelein 5-0 in the top of the fourth inning, Buffalo Grove didn't flinch.
And when the Bison rallied to close the gap to 8-6 in the sixth inning and Mundelein brought in Mitch Schulewitz, one of the area's top pitchers, still Buffalo Grove was nearly emotionless.
But the Bison did finally explode when right fielder Nick Capinelli caught a flyball for the final out of the game as Buffalo Grove rallied to stun Mundelein 11-9 Thursday at the St. Viator regional in Arlington Heights.
"This is huge," said Ryan Shumi, who had 2 hits and two great defensive plays in the seventh inning. "Everyone had such high expectations that they would win. But we didn't believe that at all. We came out strong, and we came out swinging."
Buffalo Grove coach Jeff Grysbash, whose team banged out 13 hits, was not amazed by his team's comeback.
"This is the third or fourth time we have come back like this," Grybash said. "We said before this game that he most beautiful thing about the playoffs is that it is not over, and anyone can be a hero. And our kids came out to all be heroes today."
Buffalo Grove (12-16) got huge days at the plate from both Josh Guertler and Luke Potnick.
Guertler, who leads the team in strikeouts, had a career-day, banging out a pair of doubles and belting out a 2-run homer to knock in 6 runs for the day.
"Hands down, it was my best day of the year and the best day of my career," Guertler said. "You just have days . . . and today was my day."
Potnick, who was the starting pitcher and left in the bottom of the fourth, produced at the plate. The senior, who had not played high school baseball before this year, had a 2-run home and an RBI triple.
"I just want to compete," Potnick said. "I thought my homer was a momentum-swing, and my triple was huge too."
Mundelein (27-5) looked like a No. 1 seed early, building a 5-0 lead after 3 innings.
The Mustangs got a 350-foot homer from Ryan Dolan in the first. They then loaded the bases in the third without a hit and scored 2 runs when Schulewitz reached on an error. They tallied two more times on a single by Mike Mertz.
Guertler's 2-run homer in the fourth cut the lead to 5-2.
Mundelein answered by scoring three times in its half of the fourth. Will Farmer and Dolan each had RBI singles, and Schulewitz drove in the other run on a fielder's choice to make it 8-2.
Buffalo Grove, which rallied from a 6-0 deficit on Monday against Waukegan in a play-in game, began to fight back. Potnick's 2-run homer got it started for the Bison. Guertler later added a 2-run double with two outs as Buffalo Grove cut the lead to 8-6.
"We just kept fighting," Grybash said. "And when they went to #6 (Schulewitz), we fought even more."
Facing Mundelein's ace, the Bison scored 5 runs.
After a walk to Dan Levato, Potnick belted a triple to center and then scored on a throwing error to tie the game. After Schumi reached on a bunt and Mike DiVesti reached on an error, Sean Edgar doubled to score Schumi. Guertler then doubled in both of them as the Bison led 11-8.
Jon Niemann, who relieved in the fourth, kept the Mustangs corralled. He'd been chased early in Monday's game but allowed just 1 run in the final 3-plus innings to pick up the victory.
"I wasn't going to be satisfied with my last outing on Monday," Niemann said. "And I knew I had to leave it all on the field today, and I did."
The Buffalo Grove rally gave Schulewitz (10-1), who was nearly untouchable all season, his only loss of the year.
"It's heartbreaking," Mundelein coach Todd Parola said. "And it is very tough for our seniors. But they outplayed us. It's just plain and simple."
Blankshain also had 2 hits for Buffalo Grove while Farmer, Dolan and Zach Osisek each had 2 hits for Mundelein.
Buffalo Grove advanced to meet the winner of Friday's Fremd-St. Viator game for the regional championship at 1 p.m. Saturday.