Both starting pitchers, Luc Rennie for Evansville and Zac Westcott for Windy City, were strong through six innings as the game was scoreless going into the seventh inning.
Brandon Dulin broke the 0-0 deadlock in the top of the seventh with a solo home run, his first of the year.
The Thunderbolts had a chance to tie the game in the bottom half of the inning with runners at first and third, but a double play turned by shortstop Toby Thomas got Rennie and the Otters out of the jam.
Thomas then doubled the Otters lead in the top of the eighth with an RBI double, extending his hitting streak to 10 games.
Mitchell Aker entered and closed the game in the bottom of the ninth to earn his fifth save of the season.
Rennie tossed a strong seven innings, allowing just three hits and walking none while striking out six to earn his second win of the season.
Westcott was dealt a tough loss for Windy City after throwing seven innings, allowing five hits and just the one run while striking out 11.
The two teams will be back in action from Standard Bank Stadium at 10:35 a.m. Wednesday.
For game two, the Otters will turn to right-hander Randy Wynne. Wednesday will be Wynne’s first start of the year. In four appearances this season, Wynne has thrown 7.1 innings while allowing just two earned runs and striking out eight.
Wynne will go up against Thunderbolts’ southpaw Patrick Ledet. Wednesday will be Ledet’s third start of the season. In 14 innings this season, Ledet has allowed just one earned run and struck out nine hitters.
Games two and three of the series will be exclusively on the Otters Digital Network presented by Kruckemeyer and Cohn. Sam Jellinek (play-by-play) will have the call for both contests.
The Otters will return home for a three-game series May 30-31 against the Florence Freedom. Wednesday, May 30 will be a doubleheader, starting at 5:05 p.m. and is Deaconess Hospital Skilled Nursing Facility Night. The series finale on May 31 starts at 6:35 p.m. and will be the first Thirsty Thursday of the season with special price drafts.
Fans can also follow Otters social media on Facebook, Twitter and Instagram for game updates throughout the day.
The Evansville Otters are the 2006 and 2016 Frontier League champions. Season tickets, group outing packages, and single game tickets are on sale now for the 2018 season.