Cam Blake drew a one-out walk for the Aggies (37-19-1) and advanced to second on a grounder to set up the winning hit.
Texas A&M will face No. 3 seed Georgia on Wednesday, when the format switches to double elimination.
Ducoff and Mikey Hoehner both homered with two outs in the eight for Texas A&M.
The Gators (33-24) were eliminated from the tournament after rallying with two runs in both the eighth and ninth innings. Will Dalton and Austin Langworthy had RBI triples in those innings.
Kasey Kalich (2-1) earned the win after pitching the final two innings for the Aggies, including a scoreless 10th. Nolan Crisp (4-4) took the loss.
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