Freshman Kentavious Caldwell-Pope also had a career night for Georgia (9-6, 0-1) with 22 points.
Alabama (12-3, 1-0) got 17 points from Tony Mitchell, who had a big Swainsboro, Ga., cheering section watching.
Trevor Releford added 12 for the Crimson Tide.
Lacy outdid his previous career-best of 12 points with 17 first-half points as Alabama led 38-26 at intermission.
TENNESSEE 67, NO. 13 FLORIDA 56
In Knoxville, Tenn., Kenny Hall scored a season-high 13 points as Tennessee upset Florida to open the conference season.
The Gators came in averaging 85.4 points this season, best among SEC teams and fifth in the nation. The Volunteers held them to 35.7 percent shooting while hitting 51 percent of their own attempts.
The Vols (8-7, 1-0) hit 12 of 22 shots in the second half to expand their lead.
Kenny Boynton and Erik Murphy each hit 13 points to lead Florida (12-4, 0-1).
LOUISIANA STATE 81, MISSISSIPPI 55
In Baton Rouge, La., Justin Hamilton and Storm Warren each had a double-double, and Louisiana State defeated Mississippi.
Hamilton had career highs with 23 points and 16 rebounds.
Hamilton made nine of his 12 field goal attempts. Warren matched his season-high with 15 points and collected 11 rebounds.
Warren replaced Johnny O’Bryant, who broke his hand Wednesday, in the starting lineup.
The 26-point victory was the largest for the Tigers (11-4) against an SEC opponent since they beat Georgia 81-52 six seasons ago.
The Rebels (10-5), who have lost four of their past five games, had no player score in double figures.
VANDERBILT 65, AUBURN 35
In Nashville, Tenn., John Jenkins scored 17 points and Jeffery Taylor added 16 as Vanderbilt routed Auburn, opening Southeastern Conference play with the Commodores’ fifth consecutive victory.
The Commodores (11-4, 1-0) improved to 49-11 all-time in SEC openers at Memorial Gym.
Auburn (10-5, 0-1) now has lost four of six overall, and the Tigers have lost five consecutive SEC openers.