In a game that lasted three hours and 34 minutes, runs were hard to come by on Thursday night at Bosse Field.
The Otters sent Jake Welch to the mound, who looked good early as he retired the first six batters he faced in order.
Welch ran into trouble in the top of the third, surrendering a few singles to River City, but was able to get out of the jam with a double play.
The Rascals countered with Brandon Feldmann, who allowed only a run on six hits while tossing 10 strikeouts earlier in the season against the Otters.
Evansville was able to get to Feldmann in the bottom of the third.
With one out, Jack Meggs singled, and moved to third on a double from Ryan Long.
With runners on second and third, MacNamee grounded out to Trevor Achenbach at second, scoring Meggs to give the Otters a 1-0 lead.
Welch ran into trouble in the sixth with the bases loaded and one out, but the right-hander struck out Achenbach and forced Kameron Esthay to fly out to centerfield to end the threat.
Welch would go into the eighth inning, holding a 1-0 lead.
Kalawaia led off the top of the eighth with a single and moved to second on a sac bunt from Andrew Penner.
Welch would be pulled for reliever Cam Opp. Welch went 7.1 innings, allowing eight hits, and struck out eight. He would end up with a no-decision.
After Mike Rizzitello threw out Kalawaia from his knees trying to advance to third, Opp had a two-strike count to Nolan Meadows.
With the bases empty, Meadows hit a solo home run to tie the game. Meadows also had a big grand slam on Wednesday.
The game would be tied 1-1 heading to the bottom of the ninth and giving the Otters a chance to win the game.
The Otters would force the bases loaded in the bottom of the ninth on a leadoff single by Taylor Lane, a one-out walk to Hunter Cullen, and a two-out walk to Rizzitello.
Rascals reliever Anthony Herrera, who took over for Feldmann to begin the ninth, got David Cronin to fly out to send the game into extra innings.
Feldmann allowed one run on four hits with eight strikeouts in eight innings pitched. He also ended up with a no-decision.
The game would be scoreless after 10, and the Rascals could not score in the top of the 11th, starting with a runner at second base due to the international tie-breaker rule.
Otters closer Taylor Wright threw 2.1 scoreless frames, lefty reliever Anthony Arias struck out lefty Kameron Esthay, and righty Drew Beyer forced pinch-hitter James Morisano to fly out.
MacNamee started the bottom of the 11th on second as the international tie-breaker runner with Keith Grieshaber at the plate.
MacNamee advanced to third base on a wild pitch from Vernon with one out and then touched home on the second wild pitch from Vernon. The ball bounced in front of the catcher Morisano, rolled towards the first base side, which was enough room for MacNamee to come home.
Vernon earned the loss, dropping his record to 4-2. Beyer earned the win, improving his record to 2-3.
After winning an important series against postseason contender River City, Evansville will now look ahead to the weekend as they welcome the Gateway Grizzlies to Bosse Field for a three-game series.
First pitch Friday is at 6:35 p.m. from Bosse Field.
