Michigan State stole a miracle road win from rival Michigan on Saturday, 27-23, in a game with an unforgettable finish.
Michigan senior punter Blake O'Neill fumbled a punt snap with 10 seconds remaining and it was scooped up by Spartans defensive back Jalen Watts-Jackson, who returned it 38 yards for a game-winning touchdown as time expired in regulation.
Harbaugh said the crushing loss will put "steel in our spine," according to Nick Baumgardner of mlive.com.
"What can you say? You've got to believe I guess," Spartans coach Mark Dantonio told ESPN.
Dantonio later alerted reporters that Watts-Jackson was hospitalized after the game with a broken or dislocated hip, according to the Detroit Free-Press.
Michigan State remains unbeaten with the win at 7-0, while Michigan coach Jim Harbaugh suffered his second loss of the season, and first in Big Ten action, in heartbreaking fashion. The unlikely play capped what was an old-school defensive battle, as neither team could generate a rushing attack. Michigan State ran for just 58 yards on 33 carries, while Michigan was almost identically ineffective (62 on 33). Spartans quarterback Connor Cook, one of the top senior quarterback prospects for the 2016 NFL Draft, completed 18 of 39 passes for 328 yards and a touchdown.