Saint Mary-of-the-Woods struck first, with Jaleigh Crawford doubling to the wall in left-center field to score Justyce Rohrabaugh in the top of the first inning.
But No. 8 Georgia Gwinnett, the host for the NAIA Lawrenceville Opening Round, held the Pomeroys' high-powered offense in check the remainder of the game to win 4-1.
The Pomeroys (36-15) will face Coastal Georgia, a 2-1 loser to Indiana Tech in eight innings Monday, in an elimination game Tuesday.
Summer Rocha pitched well but the Grizzlies picked up picked up eight infield singles, using their speed in addition to some good fortune on a couple of incorrect calls at first base.
The Grizzlies evened the score, 1-1 in the bottom of the first, putting two runners on with infield singles and scoring on a throwing error by Jaselyn Conn.
Georgia Gwinnett took a 2-1 lead in the third. Lindzie Owen reached on a questionable call at first base to start the Grizzlies' rally. She advanced to second on a sacrifice bunt, stole third and came home on an infield single by Madison Rodgers.
Rodgers tacked on an RBI infield single in the fifth to make it 3-1.
"Summer threw well. We didn't play terrible," coach Jim Walker said. "A couple calls go (the Grizzlies) way and that changed momentum a little bit;. Any time you give the No. 8 team in the country extra outs, it's tough. We've got to be a little bit better defensively."
The Pomeroys left five runners stranded and struck out 10 times.
Rylee Pender and Jasmine Kinzer came through with back-to-back singles in the fifth against Kailyn Berry (8-4). That caused Georgia Gwinnett to go to ace Annalise Wood, who struck out six over 2 2/3 innings to earn the save.
Their pitchers are good. They move the ball well, but honestly I don't think they're anything better than we've seen all year long," Walker said.
The Pomeroys will face Coastal Georgia at 12:30 p.m. Tuesday in an elimination game.  The winner of Saint Mary-of-the-Woods vs. Coastal Georgia will return to the diamond Tuesday at 3 p.m. for a second elimination game.