The Golden Eagles (10-7, 2-2 Big East) led by as much as 16 before familiar struggles on offense re-emerged in the second half. The Pirates (10-7, 1-3) took advantage and got within 65-63 with 23.3 seconds left off a 3 by Brian Oliver (15 points). He hit 3s on back-to-back possessions.
But Mayo hit two foul shots to get the lead back to four and Fuquan Edwin's layup rolled off the rim with 5 seconds left. Sterling Gibbs hit a desperation 3 from nearly midcourt as the game clock expired, though the Golden Eagles walked off in relief with a one-point victory.
Marquette, the lowest-scoring team in the league, watched its lead nearly evaporate after halftime because of empty possessions and more aggressive play on the offensive end by Seton Hall.
The Pirates kept chipping away but could never get over its big early hole. The Golden Eagles had shot 56 percent in the first half to take a 14-point halftime lead.
Momentum switched after halftime.
Oliver's 3 got Seton Hall within 63-60 with 1:55 left after Wilson was whistled for traveling.
Gibbs' attempted layup on the next possession bounced high off the rim, and Wilson hit two foul shots with 41.8 seconds left to make it a two-possession game before Oliver was clutch again from long range.
But in the end, Seton Hall came up one possession short. The Pirates had another disappointing trip to Milwaukee, where they're 0-7 against Marquette since 2007.
Mayo had a terrific day from the floor, shooting 4 of 6 from the field, including 2 of 3 from 3-point range, and hitting all nine of his foul shots. Wilson added 11 rebounds.
First-half struggles proved to be too much to overcome for Seton Hall, which went nearly four minutes without a field goal. It allowed Marquette to stretch a six-point lead to 14 at the half against the Big East's worst scoring defense (72.6 points per game).
Manga's reverse in transition got Seton Hall back within 31-23 with 3:35 left in the first half, before Marquette's Derrick Wilson (eight points, four assists) came up with two clutch buckets with the shot clock winding down on each possession.
The Golden Eagles have had trouble scoring this season, so Wilson's baskets were big. One came after flipping up a layup that rolled around the rim before falling through.
Then Wilson hit short jumper near the lane for a 36-23 lead with about 1:30 left, before Mayo's contested 3 from the wing helped the Golden Eagles take the 40-26 lead at the half.
Follow Genaro Armas at http://twitter.com/GArmasAP