Adam Eaton's sacrifice to center in the seventh inning scored Daniel Kaczrowski, who had led off with a double to left, to provide the difference in Mobile's 2-1 Southern League victory over the Chattanooga Lookouts on Sunday.
Chattanooga (37-26) remained a game ahead of Tennessee (36-27) in the North Division's second-half race, as the Smokies fell to Jacksonville.
The Lookouts tied the game earlier in the seventh when Scott Van Slyke singled to right to score Alex Castellanos, who reached on an infield hit and advanced to third on a throwing error on a pickoff attempt.
Game five of a six-game series in Mobile is tonight at 8:05.
Will Savage (12-5, 3.84) is scheduled to start for the Lookouts, with Charles Brewer (4-1, 2.70) scheduled for the BayBears.