Pat Fitzgerald's highly anticipated reunion with Northwestern ended in heartbreaking fashion Saturday.

The No. 25 Wildcats rallied from an eight-point fourth-quarter deficit to defeat Michigan State 24-21, spoiling Fitzgerald's first matchup against the program he previously led for 17 seasons.

Northwestern improved to 5-1 with the victory, while Michigan State dropped to 2-5 after another frustrating conference loss.

The matchup carried additional significance because Fitzgerald was facing his alma mater for the first time since becoming Michigan State's head coach.

However, for much of the afternoon, it appeared the Spartans would deliver their coach an emotional victory.

Michigan State entered halftime leading 14-10 after quarterback Alessio Milivojevic connected with Bryson Williams for a touchdown late in the second quarter.

Northwestern responded with a field goal in the third quarter, cutting the deficit to 14-13.

The Spartans then appeared to take control early in the fourth quarter when Milivojevic found Chrishon McCray for a 53-yard touchdown, extending their advantage to 21-13.

But Northwestern refused to go away.

Quarterback Aidan Chiles, who previously played for Michigan State, helped lead the Wildcats on a crucial scoring drive. Chiles finished the possession with a 1-yard touchdown run before connecting with Alex Honig for the two-point conversion, tying the game at 21.

Michigan State had an opportunity to regain the lead after Northwestern failed to convert a fake punt, giving the Spartans possession deep in Wildcats territory.

However, Liam Boyd's 33-yard field goal attempt was blocked in the final minute.

Northwestern capitalized on the missed opportunity.

Chiles directed a 64-yard drive that positioned the Wildcats for the game-winning field goal with just two seconds remaining.

The dramatic finish handed Michigan State another difficult loss after the Spartans fell 38-37 in overtime against Illinois last weekend.

Saturday's loss carried an added sting for Fitzgerald. After nearly two decades leading Northwestern, he watched his former program rally past the Michigan State team he now coaches.

The defeat also extended his search for his first Big Ten victory with the Spartans, while Northwestern continued building momentum during its impressive start to the season.

The Wildcats walked away with another comeback victory and growing confidence. Fitzgerald, meanwhile, was left with a frustrating reality: The program he once helped build found a way to finish the game his new team could not.