The Spartans beat LSU 80-63 for a 10th trip to the Elite Eight under Tom Izzo. Aaron Henry had 20 points, eight rebounds and six assists for the second-seeded Spartans.
Freshman Gabe Brown also had 15 points, an unexpected contribution from a player who had never scored more than 11.
Big Ten Player of the Year Cassius Winston added 17 points and eight assists for the Spartans (31-6).
Michigan State advances to play Duke at 5:05 p.m. Sunday in the East Regional Final on CBS.
Tremont Waters had 23 points for third-seeded LSU, which finished 3-2 under interim coach Tony Benford. He took over when head coach Will Wade was suspended indefinitely amid reports about an FBI investigation.