Jonah Mueller had two opponents to battle on Thursday.

One donned the blue pinstripe uniforms in the opposite dugout. The other couldn’t be seen, but was daunting nevertheless.

But Mueller beat both the sweltering heat and Glenwood City on Thursday afternoon. With temperatures sitting in the 90s and the sun beating down on Carson Park, Mueller dealt the Immanuel Lutheran baseball team past the Hilltoppers 10-0 in five innings in the Lancers’ Division 4 playoff opener.

“I’m a little gross right now,” Mueller said after the game. “It’s definitely hot out here.”

But, he said, it was well worth it.

Mueller pitched four innings of two-hit baseball and struck out six to push the second-seeded Lancers into the regional semifinals.

“My location was there today, and I didn’t have to work with a lot of guys on base which always helps,” Mueller said. “Everything seemed to be working well.”

And the defense did its job behind him. While the Lancers (17-2) benefited from six Glenwood City errors offensively, they didn’t return the favor. Immanuel Lutheran played clean defense all afternoon, putting a zero up in the errors column.

At this time of year, that can make the difference between moving on and going home.

“Our formula most of the year has been pitching and defense, and then scoring enough runs to get the ‘W,’” Lancers coach Joe Lau said. “Any time we’re playing clean defense and our pitcher is throwing strikes, we have a pretty good feeling about our chances.”

Gavin Janson and Max Janson got the Hilltoppers’ only two hits, singles in the second and fourth innings, respectively.

Mueller only issued one free pass, a walk to Jayden Quinn in the third inning.

“He’s always effective when he can get ahead in counts, and I think he did that for the most part,” Lau said. “For the most part, he battled pretty well in difficult conditions today.”

Immanuel Lutheran scored once in the first, twice in the second and third and five times in the fourth.

Mueller and Isaiah Plath both went 2 for 3 at the plate to lead the Lancers. Ryan Zimmerman and Britten Rutz drove in a pair of runs each.

Zimmerman set the side down in order in the top of the fifth to close out the win for the Lancers.

Seven of the 10 runs Gavin Janson gave up on the mound for Glenwood City were unearned.

“The big thing I was looking for today was that we didn’t have any letdowns,” Lau said. “We had a big week last week, and I didn’t want this to be a trap game where you’re looking ahead. Glenwood had a pitcher who threw strikes. It could have been a much closer game.”

Immanuel Lutheran, the champion of the Dairyland Conference, will face Clear Lake in the regional semis on Tuesday. Clear Lake was the runner-up in the East Lakeland Conference this spring.

The Lancers were ranked fifth in Division 4 in the final Wisconsin Baseball Coaches Association poll of the season. They’re in a tough regional though — second-ranked Boyceville is the No. 1 seed.

“Confidence is high right now,” Mueller said. “We’ve had a really good year and we’re playing well.”

Immanuel Lutheran 10, Glenwood City 0

GC 000 00 — 0 2 6

IL 122 5X — 10 8 0

WP: Jonah Mueller (4 IP, 2 H, 0 R, 6 K, 1 BB). LP: Gavin Janson (4 IP, 8 H, 10 R, 3 ER, 1 K, 2 BB). Leading hitters: Immanuel Lutheran: Mueller 2-3 (2B), Isaiah Plath 2-3 (RBI), Ryan Zimmerman 1-3 (2 RBI), Britten Rutz 1-3 (2 RBI).