Oliver finished with 19 points and 10 rebounds for the Flyers (16-12, 6-8 Atlantic 10 Conference), who have won two in a row.
Dayton led the majority of the first half and never trailed after halftime, but had a tough time holding off the Spiders. The Flyers had a seven-point advantage midway through the second half, then had their lead trimmed to 60-59 when Richmond's Cedrick Lindsay made a free throw with 6:11 left.
But the Spiders (17-12, 7-7) were unable to tie or pull ahead. Dayton's Josh Benson and Dyshawn Pierre each followed with a free throw, then Dillard converted a three-point play to push the Flyers lead to six and hold on.
Lindsay had 22 points and seven assists for Richmond.
An attorney for former Southern Mississippi basketball coach Donnie Tyndall says the NCAA's Committee on Infractions missed its deadline to respond to the coach's appeal.
The Northwoods baseball league swapped the traditional baseball diamond for the waters of Lake Michigan to host their HR derby.
Sources tell ESPN's Jeff Goodman that the South Florida men's basketball program is under NCAA investigation for possible academic fraud issues.