"We were in there for a long time because we made a lot of mistakes," Boss said. "These are all mistakes that are, in my opinion, preventable mistakes. I think they're all mental errors, and there's no excuse for that."

The Spartans have committed three or more errors in each of their past three games and are averaging more than one per game this season. Junior shortstop Randy Seymour, for the second straight year, leads the team in errors with 15 — including one on Friday.

Northwestern’s Owen McElfatrick led the way offensively, going 3-for-6 with three RBIs and a double.

Sophomore right-hander Logan Pikur made his first Big Ten start and third start of the season. He lasted two innings, allowing six runs — four earned — with two walks and a strikeout.

Pikur has struggled this season, allowing multiple earned runs in five of his outings despite averaging just over an inning per appearance.

Across 14 appearances, Pikur holds a 9.00 ERA with 6.75 strikeouts per nine innings and 5.4 walks per nine.

Boss said sophomore left-hander Joseph Dzierwa, the usual Friday night starter, was given an extra day of rest, prompting the start for Pikur.

"Joseph is our Friday guy, but he threw 80 pitches on Sunday," Boss said. "We wanted to give him an extra day. Higgins threw a lot of pitches on Monday, so he only had three days of rest. So, today turned into a bullpen day."

Five pitchers appeared for MSU, combining to allow eight earned runs and four walks. The Spartans struck out 14, including five from closer Tyler Horvath over three innings.

Northwestern struck early with two runs in the first. After Owen McElfatrick and Will Lilios reached base, Jackson Freeman singled to right field, scoring one. A throwing error by sophomore right fielder Parker Picot allowed a second run to score, giving the Wildcats a 2-0 lead.

Plays like that have defined MSU’s season — missed opportunities to end innings turning into costly defensive miscues that opposing teams have capitalized on.

While defensive mistakes have been a recurring issue for MSU, they aren’t the only reason behind the team’s five-game losing streak.

Following Wednesday’s loss to Central Michigan, Boss said changes were coming to the lineup and pitching rotation. Outside of ace Joseph Dzierwa, MSU pitchers have struggled — combining for a 7.08 ERA.

Even though the Wildcats put up runs early, MSU put in its best comeback effort of the season. Responding to a two-run spot in the first, Sam Busch blasted his ninth homer of the year, tying things at two.

After six innings, Northwestern led 9-3. But MSU stormed back with seven runs across the seventh and eighth to take its first lead of the game. Busch came up in another clutch spot with the bases loaded and singled through the left side, driving in two to cut the deficit to 9-5.

Northwestern, the Big Ten leader in hit batters this season, plunked five Spartans on Friday. In the eighth, the Wildcats hit two and walked another to load the bases. Senior JT Sokolove singled to score one, and sophomore Ryan McKay — who averages nearly a walk per game — drew a free pass to plate another.

Graduate catcher Caleb Berry reached on a fielder’s choice, and a Wildcat throwing error allowed MSU to tie the game. Busch then gave the Spartans a 10-9 lead with a sacrifice fly.

Busch went 3-for-4 with five RBIs and a walk — his first five-RBI performance since MSU’s win over Illinois on March 29.

"I think Sam's showing great leadership on the field, and we need more of that, and unfortunately, right now, I think Sam's one of the only guys," Boss said. "I think we get pretty good leadership out of JT Sokolov, Ryan McKay and Caleb Berry. Those four guys are making us go right now, and so we need more guys to act like those four guys."

In the ninth, graduate right-hander Tyler Horvath took the mound. Horvath entered with five saves on the season and a 3.60 ERA. But Northwestern’s Ryan Kucherak led off with a solo home run to deep left-center, tying the game at 10.

In extra innings, the Spartans couldn’t string together any offense, while Northwestern pushed across the go-ahead run in the 11th to take game one of the series.

"They need to figure it out," Boss said. "There are things that we've been working on since September, and this is a different team than what showed up early in the season in North Carolina and South Carolina. We've talked about being consistent all year long. When we're consistent, we're pretty good, but we're not consistent.”

MSU will look to snap its five-game losing streak when it faces Northwestern again on Saturday. First pitch is set for 3 p.m., with the game streaming on Big Ten Plus.