ANN ARBOR, Mich. -- Michigan and Michigan State don't play until next week, but the Spartans' faithful have already thrown the first punch.

In green marker, on the wall of a press box bathroom in Michigan Stadium, someone has scrawled the 27-23 final score of 2015's wild meeting between the two rivals.

It was a year ago this week that a botched Michigan punt turned into a 38-yard touchdown return with no time left on the clock. Depending on what colors you wear, it was either the most incredible or painful chapter of the storied history between the two programs.

The loss was the Wolverines' second in its first year under coach Jim Harbaugh. The win buoyed the Spartans' chance to win their second Big Ten title in three years. Michigan State went on to beat Iowa in the league title game and reach the College Football Playoff. Jalen Watts-Jackson, the sophomore special-teams player who became an overnight legend in East Lansing, watched the rest of the season from campus. He broke his hip on a final lunge to reach the Michigan Stadium end zone and secure the win.

The fortunes of the two teams have headed in opposite directions since then. No. 3 Michigan is undefeated heading into this weekend's homecoming game with Illinois. Michigan State has lost four straight games to fall to 2-4 at the halfway point of this season. The Spartans may struggle when they host Michigan next Saturday, but the green-and-white fans at least got one stinging blow in before the game.