Derrick Williams led the Spiders with 16 points, and Kendall Anthony added 13 points. The Spiders (3-1) were outrebounded 41-30 and squandered a 49-42 lead they built by holding the Gophers scoreless for more than four minutes.
Mbakwe has been starting on the bench after reconstructive surgery on his right knee ended last season for him after the seventh game. But he was on the floor with Williams, Joe Coleman and both Hollinses — Andre and Austin — for long periods in this game.
Austin Hollins finished with 13 points and Coleman had 10 points for the Gophers, who are 45-1 at Williams Arena in nonconference games in six seasons under coach Tubby Smith, whose preference has been to load up the schedule with mid and low-major teams and mostly limit the big-time opponents to neutral-site games at tropical holiday tournaments. That includes the Battle 4 Atlantis event next weekend, with Duke, Memphis and Missouri among the heavyweight entrants.
Richmond sure made Minnesota work for this one, and the Spiders didn't even make much happen from 3-point range, which is one of their strengths. They went 3 for 14 behind the arc in the first half and finished 4 for 20.
With help from 11 Gophers turnovers in the first 12 minutes, the Spiders led 22-13 with about 7½ minutes left until the break before the Gophers built some badly needed momentum.
They got most of it from Williams, their energetic, athletic, vastly improved senior who flourished last season at power forward when Mbakwe was out. Williams had three baskets in a 96-second stretch, then tipped a ball as he fell backward at the key to keep an offensive rebound alive and set up a dunk by Mbakwe off a perimeter pass from Andre Hollins that cut the Richmond lead to 25-22. Coleman's free throw made it 30-29 Minnesota, the first lead by the home team in more than 16 minutes.
The Spiders opened their season with home victories over Liberty, North Carolina-Wilmington and Hampton, holding all three opponents to 58 points or fewer in their first 3-0 start in six years. The last time they opened with four wins in a row was 1985.
With four of their top five scorers from 2011-12 returned, the Spiders were picked to finish 10th out of 16 teams in the preseason Atlantic 10 Conference poll by the coaches and media covering the league.
During nine seasons under coach Chris Mooney, the Spiders have beaten a team from each of the major six conferences, including 11 of their last 17 entering this game. They play at No. 7 Kansas on Dec. 18. Their last win over a Big Ten opponent was two years ago against then-No. 8 Purdue.
The only other time Richmond and Minnesota met was 2002 in the NIT, a 67-66 victory here by the Spiders.
Minnesota's only nonconference home loss under Smith came to Virginia in the ACC-Big Ten Challenge two years ago.