The 14th-seeded Bears with a starting lineup of five seniors came back from five points down in the last 4:52 as Duke's offense collapsed.
They sent home one of the true blue-blood programs, coached by Hall of Famer Mike Krzyzewski and starring freshman Jabari Parker, sure to be one of the top NBA picks this year. Mercer is coached by former Oklahoma Baptist player Bob Hoffman, who has banged around the coaching ranks from women's teams to the American Basketball Association to the Rio Grande Valley Vipers of the NBA Developmental League.
Next up: 11th-seeded Tennessee, which upset sixth-seeded Massachusetts 86-67, on Sunday in the third round.
Jakob Gollon scored 20 points and Daniel Coursey scored 17, helping the Bears overcome a season-high 15 3-pointers from Duke.
Mercer scored 11 straight points during the late 20-5 run that clinched the biggest victory in school history and sent the Blue Devils to their second first-game exit in three years.
Wichita state 64, Cal Poly 37 • In St. Louis, Cleananthony Early had 23 points and unbeaten Wichita State faced no resistance from Cal Poly, going to 35-0 for the best start in NCAA history with a rout of Cal Poly.
The Shockers (35-0) dominated from the tip-off against the only team with a sub-.500 record in the tournament. With the exception of Early, most of the glaring numbers were on defense. The losers managed 13 points in the first half and shot 21 percent.
Malik Love had nine points for Cal Poly (14-20), which won the Big West tournament as the No. 7 seed and beat Texas Southern in First Four game before being held to a season low for points. Chris Eversley, the Big West tourney MVP and coming off a 19-point game, was held to six points on 2-for-14 shooting.
Tennessee 86, UMass 67 • In Raleigh, N.C., Jarnell Stokes scored a career-high 26 points and grabbed 14 rebounds to lead Tennessee.
Jordan McRae added 21 points for the Volunteers (23-12), the No. 11 seed in the Midwest Regional. Tennessee had little trouble with the sixth-seeded Minutemen (24-9), shooting 54 percent from the field and handling UMass' fullcourt pressure in a surprisingly one-sided performance that included another solid defensive showing.
Kentucky XX, Kansas State XX • Ad modi officimodit quianihiciis sum quodite velliquod magnihiliqui nissunture, optius, comnihil ent pratinctur, quo eatur? Ovid ullab int minvernatet expe magnat hilit vel inum volupta tibusa Atur accus eniasit, eum accum endebit essimperis magnam.