In the eighth, Power rightfielder Junior Sosa, the No. 9 hitter, reached on a looping single. He seemed caught in a rundown on a pickoff attempt, but the throw from Gnats first baseman Brian Harrison went into center field, sending Sosa to third.
Power designated hitter Alen Hanson then collected the game-winning RBI with a bloop to short left field.
The Power had but five hits, two by Hanson, but fell back on the pitching.
"I pretty much had everything working for me today," said Fuesser, who relies on a change-up and spots a fastball. "I had that quick, fast tempo, which kept them on their toes. I mixed all my pitches in there. Got them off-balance. Had their wheels turning in their heads. They didn't know what I was going to throw."
He finished with eight strikeouts. Cooper finished with back-to-back 1-2-3 innings.
"He has quality stuff," Sofield said of Cooper. "He's down in the zone. He's crisp with a sinker-slider ... When the game's on the line he likes the ball in his hands - and I like giving it to him."
The Power will host the 11-9 Sand Gnats today at 7:05 p.m.
Reach Mitch Vingle at 304-348-4827, mitchvin...@wvgazette.com or follow him at twitter.com/MitchVingle.