The Eagles defeated Kent City 5-3 and Newaygo 6-2 to reach the finals, then downed Fruitport 10-0 in the title game.
Oakridge is now 7-0 on the season.
Fessenden was the winning pitcher in all three games, striking out a total of 30 while only giving up eight hits and two walks. She also stood out at the plate with six hits on the day, including a homer run and triple.
Other offensive standouts for Oakridge were Abby Lowe with four hits and Hannah Reinhold with a three-run homer.
“I was very pleased with how our girls competed,” said Oakridge Coach Joe Coletta. “It was a long day and our first tournament of the season, so to come out on top against good competition was a very good indication as to where we are mentally.
“Maintaining a high energy level for three games is not easy, so I’m pleased at this point.”