The Rockets trailed 1-0 entering the bottom of the sixth inning before scoring three times to get within three outs of advancing to the winner's bracket, but could not hold the lead, allowing the Cougars to tie the game in the seventh on an RBI single by Seven Barker.
It was a pitcher's duel for much of the night as Forrest's Zach Horvath and MTCS's Ivy Starling locked horns with the duo allowing zero runs combined through the first five innings.
In the home half of the inning, Horvath led off with a single to right, and after a Rocket strikeout, Paten Pruitt made it first and third with a sharp base hit to right field.
Rocket backstop Richard Hardin came through with a game tying single and Ryan Daughrity followed with a long two-run double to the fence in left-center, giving Forrest a 3-1 lead, entering the top of the seventh.
Rocket reliever Tanner Garvin beaned Kyle Howard to lead off the bottom of the seventh and another Forrest error put Cougar runners on first and second.
A 6-4 fielder's choice off the bat of Starling put runners on the corners and Starling stole second to make it second and third before Lawson Pitts drove in Justin Winn, who had come in to run for Howard.
Barker followed with the game tying base knock before Garvin escaped further damage with a strikeout.
Forrest had a chance to win the game in the home half of the seventh when Horvath and Zach Brewer banged back-to-back, two-out base knocks, but it was not to be as a fly ball to center field sent the contest to extra innings.
Both squads went down 1-2-3 in the eighth inning and the Cougars went ahead 6-3 in the ninth on consecutive RBI hits from Pitts, Barker, and Joe Warner.
Ben Brown came to the hill for the bottom of the ninth and after allowing a two-out double to Horvath; Brown induced a pop-up to shortstop to end the first round contest.
Horvath, Pruitt, and Hardin all had two hits apiece in the game, while Brewer, Daughrity, and Dillon Dowler had one base knock apiece for Forrest.
Horvath tossed six innings and gave up one unearned run on six hits, while striking out four and walking three Cougars batters.
The Rockets will play in a loser's bracket contest on Saturday with the opponent and time to be determined by the outcomes of tonight's games in Eagleville.