The Lady Tigers, last year's 3A champion, defeated last season's 1A title holder, Smithville, 6-0 at James Malone Field.
"We've got to get better," Rhea said, after watching his team scatter 11 hits in six innings. "You're not going to beat many teams playing inconsistent.
"We're up and down."
Nettleton (13-1) banged out seven hits and scored five runs in the bottom of the first inning. The Lady Tigers would not get another hit until the fifth. One of those, a single by Molly Bramlett, produced the Tigers' final run.
Defensively, despite committing two errors, Nettleton's play was solid.
One the stars was junior shortstop Lauren Baldwyn, who had a hand in nine of the game's first 15 outs.
"We've got to keep playing defense and get more hits," she said. "I guess we got comfortable after the first inning. It's not like we were trying not to hit.
"Defense is going to win games, but you've got to hit."
The Lady Seminoles (7-5) went hitless against Nettleton pitcher Anna Kent until the sixth inning when pinch-hitter Morgan Barrett singled.
Breanna Edgeworth, Smithville's No. 3 batter in the lineup, added a single in the seventh for her team's only other hit.
"We didn't hit like we're capable of hitting," she said. "We've never popped up that much. We're a better hitting team than that."
Bramlett and Brittany Adams led the Lady Tigers with two hits apiece. Harley Tucker had a two-run double in the team's five-run first inning.
"We had a great first inning," Rhea said. "That's exactly the way you want to start a ballgame. But, what happened the other six?
"That's not good. You're not going to beat many teams that way. We were fortunate to catch Smithville on an off night."