Oxford trailed 38-37 before Clark hit her game-winning shot. She finished with 11 points.
Casmine Copeland added nine points, and Lexie Higgins contributed eight.
Oxford (5-5) has won two straight and ended an eight-game win streak by Oneonta (12-3), which recorded its second-lowest scoring total of the season.
Oneonta led 20-13 at halftime.
White Plains 42, Jefferson Christian 29: The Wildcats improved to 12-1 with a home win.
Amber Greenwood had 17 points and four steals for the winners, while Sophie Taylor added 10 points.
Taylor Snellgrove had five points, five assists and five rebounds.
White Plains gets a break for Christmas before returning to the court Dec. 28 for a tournament in San Destin, Fla.
Ranburne 53, Wadley 17: Jessie Ralston and Alyssa Smith each had 14 points for the winners, while Smith added five rebounds.
Hannah Phillips contributed five points and a team-high 10 rebounds.
Ranburne (5-5) will face Cleburne County at home Saturday.
Anniston 57, Cleburne County 31: Anniston earned its eighth win of the season with a victory over Cleburne County.
Quanetria Bolton led Anniston in scoring and managed a double-double with 17 points, 16 rebounds and six blocks.
Marticia Jackson added 13 points, and Rakeema Najiy had eight. They each managed four rebounds.
The Lady Bulldogs (8-3) will play in the Fort Payne Christmas Tournament on Saturday.
Cleburne County was led in scoring by Toni Epps with eight points.
Woodland 65, Cedar Bluff 35: Woodland advanced to the championship game of the Cherokee County Invitational with its win over Cedar Bluff.
Madison Story with 12 points led the Lady Bobcats in scoring. Leah Strain and Adre Bowen each added 11.
The win improves the Bobcats to 10-0.
Cedar Bluff was led in scoring by Maligrace Wilson with 11 points.
Piedmont 66, Cedar Bluff 38: Piedmont advanced to the championship game of the Cherokee County Invitational after defeating Cedar Bluff.
Denard Spears led the Bulldogs with 21 points, while Taylor Hayes had 11 points and Darnell Jackson nine.
The win improved Piedmont’s record to 6-3. The Bulldogs (6-3) will face either Collinsville and Glencoe on Saturday.
Davion Fife led Ceder Bluff with10 points.
Alexandria 62, Saks 57: Alexandria improved to 5-3 after defeating Saks.
The Valley Cubs were led in scoring by Dakota Kelley with 11 points. Alton Davis and Tyrelle Gay both finished with 10 points.
Alexandria will play again Friday as part of the Glencoe holiday tournament against Pleasant Valley.
Saks was led in scoring by Daniel Heard with 12 points. Roc Green added 11, and Tre Smith added 10.
Wellborn 59, Pleasant Valley 48: Devron Taylor had 32 points and four rebounds for Wellborn, which improved to 3-4, including 3-1 in Class 2A, Area 10.
Corri Tignor added 15 points and 14 rebounds.
Wellborn will play again Saturday at Donoho.
Lucas Ford led the Raiders with 19 points, and Trey Phillips added 13 points. Pleasant Valley will play Saturday at home against Hokes Bluff.
Anniston 65, Cleburne County 47: Double-doubles by Quint Dobbins and Qua Frazier led Anniston to its eighth win of the season.
Dobbins finished with 17 points and 11 rebounds, while Frazier finished with eight points, 10 rebounds and 10 assists.
Demarcus Thomas added eight points, five rebounds and 10 assists, while Quindarious Jackson added 12 points and five rebounds.
On Thursday, Anniston takes its 8-3 record to the Dwight Madison Roundball Classic at Carver-Montgomery to take on Jeff Davis
White Plains 44, Jefferson Christian 36: Defense stole the show in White Plains’ game against Jefferson Christian.
The Wildcats led 18-16 at the half. Eli Hightower scored five of his 11 points on back-to-back plays midway through the third quarter to put White Plains up by five and help the Wildcats pull away.
Nathan Gilbert led in scoring and secured a double-double with 14 points and 10 rebounds.
White Plains (7-6) will play Nashville Christian on Friday in the San Destin Beach Blowout in Destin, Fla.
Errol Chandler led Jefferson Christian with 12 points.
Clay Central 64, Randolph County 59: Clay Central managed to get above the .500 mark with a win over Randolph County.
Jo Jo Staples and DeAndre Wills both led the Volunteers with 17 points apiece. Jaylon Lyles added 11 points.
Clay Central (4-3) will play again Jan. 3 on Beaureguard at home.
Randolph County was led in scoring by Elijah McFarland with 23 points.