The Vikings built a 24-point lead at one stage on the way to handing Clayton its first loss in 33 games this season.
Shaunteva Ashley scored 17 points to lead a balanced Augustana attack that saw five players reach double figures. Ashley also contributed a team-high eight assists.
Faith Tinklenberg followed with 15 points, Alex Feeney added 14, Emily Schulte scored 11 and Cami Koehn netted 10. Andrea Whitney finished with eight.
Augustana was able to overcome 16 turnovers in each half by shooting 52.8 percent from the field, including 58.8 percent from three-point range.
Clayton cranked up the heat down the stretch and eventually clawed to within seven points with two minutes remaining. However, Lydia Nelson scored on a layup, Ashley made two free throws and Tinklenberg contributed four straight points to push the margin back to double digits.
The contest was tight early on with Augustana eventually using a 9-0 run to help grab a 32-25 halftime advantage.
The Vikings then broke the game open by hitting six of their first seven shots to start the second half, including three three-pointers, two from Schulte. The 16-4 surge pushed Augie's lead to 48-29. The margin eventually ballooned to 24 points before the Lakers made things interesting down the stretch.
Clayton was led by All-America Drameka Griggs who scored 22 points.
Augustana, 28-6, now faces Dowling, 29-3, in the semifinals at 6 p.m. this evening. Both teams are making their first ever appearance in the Elite Eight.
CLAYTON STATE (32-1): Keona Dixon 2-8 1-2 7, Bena Hanyard 6-14 2-4 16, Shacamra Jackson 7-21 2-4 17, Kayla Mobley 0-6 2-5 2, Kayla Pryce 1-5 0-2 2, Arkia Armstrong 0-1 0-0 0, Jessica Covington 0-1 0-0 0, Drameka Griggs 8-18 5-8 22, Shannon Smith 1-3 0-0 2. Totals 25-77 12-25 68.
AUGUSTANA (28-6): Shaunteva Ashley 5-11 5-6 17, Alex Feeney 6-10 0-0 14, Lydia Nelson 3-6 0-0 6, Emily Schulte 4-9 0-0 11, Faith Tinklenberg 4-8 6-7 15, Emily Bose 0-0 0-0 0, Cami Koehn 2-3 4-4 10, Riley Nordgaard 0-0 0-0 0, Andrea Whitney 4-6 0-2 8. Totals 28-53 15-19 81.
Halftime score - Augustana 32-25. 3-point field goals - Clayton State 6-22 (Dixon 2-6, Hanyard 2-3, Jackson 1-4, Mobley 0-2, Armstrong 0-1, Covington 0-1, Griggs 1-4, Smith 0-1); Augustana 10-17 (Ashley 2-3, Feeney 2-3, Nelson 0-1, Schulte 3-4, Tinklenberg 1-3, Koehn 2-3. Fouled out - Hanyard. Total fouls - Clayton State 16; Augustana 19. Rebounds - Clayton State 37 (Jackson 10); Augustana 45 (Tinklenberg 8, Whitney 8). Turnovers - Clayton State 16; Augustana 32. Assists - Clayton State 12 (Griggs 3); Augustana 21 (Ashley 8). Blocked Shots - Clayton State 4 (Jackson 4); Augustana 8 (Whitney 3). Steals - Clayton State 20 (Hanyard 8); Augustana 9 (Schulte 3, Tinklenberg 3).
Scores/Pairings
NCAA Division II Women's Elite
Tuesday's Games in San Antonio
Augustana 81, Clayton State 68
Dowling 60, Colorado Mesa 44
Western Washington 80, Nova Southeastern 76 OT
Ashland 74, Gannon 63
Tonight's Final Four Pairings
Augustana (28-6) vs. Dowling (29-3), 6 p.m.
Western Washington (29-3) vs. Ashland (35-1), 8:30 p.m.
Championship Game
7 p.m. Friday