Hector Guevara drew a bases-loaded walk to force in the go-ahead run in the Biscuits' 5-4, 10-inning victory over the Chattanooga Lookouts on Monday.
Mikie Mahtook led off the inning with a single before one-out walks to Todd Glaesmann and Kyeong Kang. Guevara walked on five pitches to bring in Mahtook.
The Biscuits rallied in the ninth inning to tie it. Kevin Kiermaier's two-out triple brought in Guevara, who made his Double-A debut in Montgomery's 14-inning home loss to Pensacola on Sunday.
The back-to-back extra-inning games were the first for the Biscuits since June 2011.
C.J. Riefenhauser (4-0) gave up one hit over two shutout innings. Starter Jake Thompson posted a quality start, giving up three runs on nine hits in six innings. He left with a 3-3 tie.