Syracuse (27-2, 14-2 Big East) improved to 7-0 against ranked teams and clinched at least a tie for the Big East title. The Orange also own the tiebreaker because of the victory over the Wildcats (23-5, 12-4), who have lost three of their past four.
On a day when the top two teams in the nation - Kansas and Kentucky - both lost, the Syracuse win could move the Orange to No. 1 for the first time since 1989-90. They were 11th in the final AP poll of the 2002-03 season when they won the national championship.
With Syracuse stars from the past back for a reunion - Derrick Coleman, John Wallace, Billy Owens and Rafael Addison among them - and the fans waving orange towels donated by the Jim and Juli Boeheim Foundation, the Orange took charge in the second half.
Syracuse increased its 10-point halftime lead to a bulging 72-56 as the 6-foot-9, 260-pound Onuaku converted consecutive follows and the 6-9 Jackson slammed home a feed from Andy Rautins.
If anybody didn't think it was Syracuse's night, they had to be convinced when Onuaku converted a bank shot off the glass after getting knocked to the floor and completed the three-point play for a 16-point lead with 8:54 left.
Kris Joseph and Scoop Jardine each scored 16 points off the bench for Syracuse, Wes Johnson had 14 and Andy Rautins finished with 12 points and eight assists.
Scottie Reynolds led Villanova with 16 points, Corey Fisher had 14, Antonio Pena 13 and freshman Mouphtaou Yarou a season-high 13.
The Wildcats had won six of the previous eight games against Syracuse, including 92-82 in March 2006, when the previous attendance record of 33,633 was set in the final home game of former star Gerry McNamara.
Rautins, who missed his first three 3-point attempts, opened the second half with a 3 from the wing and Johnson followed with another that countered a three-point play by Corey Fisher.
Jackson hit a hook in the lane and converted a layup off the glass off a feed from Rautins to give Syracuse a 56-48 edge at 16:38.
After a follow by Mouphtaou Yarou, Rautins drained another 3, this one from the top of the key, and after Reynolds missed a wide-open 3 from the left corner, Onuaku converted two follows off missed 3s by Rautins to boost the lead to 65-52 with 12:03 left.
The Orange's big men then put the game away.
The Wildcats didn't seem fazed by the raucous crowd. Reynolds hit a pair of open 3s and a three-point-play by Fisher helped stake 'Nova to an early lead. A 3 from the top of the key by Corey Stokes gave Villanova a 23-14 edge midway through the first half.
But the Syracuse zone gradually became more aggressive and the openings disappeared. 'Nova missed six straight 3-pointers and scored only one basket in a span of nearly 6 minutes.
Villanova entered the game averaging 25 points a game from its bench, but Syracuse reserves Scoop Jardine and Kris Joseph combined for 21 points and keyed the comeback.
Five straight points by Jardine and a pair of free throws by Johnson gave Syracuse a 46-36 halftime lead.
Villanova shot 31.4 percent in the opening half and 27.8 percent from beyond the arc.
The Wildcats rebounded from consecutive losses to Connecticut and Pittsburgh with a 74-49 victory over South Florida on Wednesday night. Villanova's first two-game losing streak in two years had dropped the Wildcats behind Syracuse in the conference standings.
