It came at the expense of defending champion Eastern Greene -- 58-52.
The Wolverines improve to 7-2 on the season while the Thunderbirds fall to 9-2.
It was a tale of two games for the Wolverines who will now take on Linton-Stockton in Saturday night's 7:30 p.m. title tilt after the Miners upended Shakamak in the first semifinal earlier in the evening.
After seeming almost helpless to stop the Class 2A No. 7 T-Birds from grinding out a 16-6 first quarter advantage, WRV found another gear.
"I was afraid we dug a hole a little too deep to get out of," Neill said. "But we responded well, I was very pleased with the kids.
"I wasn't very pleased with the start, but the way they stuck to the gameplan and crawled back in it, I was very pleased."
Quickly erased the double-digit gap and began to build on their own lead with much more success than Eastern Greene had in maintaining theirs.
"The second and third quarter we got totally out-toughed, there's no other way to put it," EGHS coach Levi Carmichael said of his team's 34-16 deficit in the middle two frames. "They wanted it more than us, then we got the lead and relaxed and our kids did not react to it well."
Sparked by a 14-3 run to open the second frame, the Wolverines pulled ahead for good when Mitch Ingram drained a 3-pointer at the 4:07 mark to push his squad ahead 20-19.
Ingram (14 points), Michael Fisher (16 points) and Cade Hill (16 points) combined to torch the Thunderbirds for 46 of their team's total points.
"In the games you have to have kids step up and they did," Carmichael said. "And our guys, the one's that we needed to play well didn't play well, it's just that simple."
Eastern Greene countered with double-figures from two sources -- Logan Frye with 13 and Kurtis Stille with 15. Leading scorer Tyler Brough was limited to nine points on 2 of 14 shooting.
After the lead change in the second quarter, WRV managed to remain ahead despite rallies by Eastern Greene that saw them cut the margin to a single point three times.
"I knew it was going to key that we took control of the game," Neill said. "We have contrasting styles of play and I knew that whoever got control of the game had the best chance to win it.
"And we were fortunate enough at the right time to have control of it."
The final time came when Briar Martindale hit the second of two free throws with 4:19 to play in the game.
After that, it was all White River Valley -- mostly from the charity stripe -- as Eastern Greene connected on five more free tosses and a trey from Frye that cut the gap to 55-51 with just 55 seconds remaining.
Over the final two plus minutes, WRV connected on 8 of 9 free throws and added on old fashioned 3-point play from Fisher in the process.
"Last night we went 3 for 11 from the free throw line and tonight they stepped up there with confidence and knocked them down," Neill said. "We had guys step up like Mitch Ingram, who didn't score last night and that's what it's going to take for us to win."
With the loss the Thunderbirds are relegated to the third place game against Shakamak at 6 p.m. on Saturday night.
EASTERN GREENE (52) -- Briar Martindale 0-2 3-4 3, Kurtis Stille 6-6 3-5 15, Nathan Sparks 2-5 0-2 5, Logan Frye 4-9 4-5 13, Tyler Brough 2-14 4-7 9, Zak Eckerle 1-1 5-6 7, Camden Sego 0-0 0-0 0, Jacob Henderson 0-0 0-0 0. Totals 15-37 19-29 52.
WHITE RIVER VALLEY (58) -- Luke Mowery 3-5 2-3 8, Mitch Ingram 4-10 5-7 14, Michael Fisher 6-12 3-4 16, Trey Gamble 0-1 0-0 0, Cade Hill 4-5 8-8 16, Jordan English 0-0 0-0 0, Nick Johnson 1-2 0-0 2, Jonathan Koenig 0-0 0-0 0, Justin Barnett 1-2 0-1 2. Totals 19-37 18-23 58.
Eastern Greene 16 7 9 20 -- 52
White River Valley 6 20 14 18 -- 58
3-point shooting -- Eastern Greene 3-19 (Frye 1-6, Brough 1-8, Sparks 1-3, Martindale 0-2), White River Valley 2-6 (Ingram 1-4, Fisher 1-1, Gamble 0-1). Rebounds -- Eastern Greene 16 (Stille 5), White River Valley 32 (Ingram 6, Johnson 6). Steals -- Eastern Greene 6 (Brough 2, Sparks 2), White River Valley 7 (Hill 4). Blocks -- Eastern Greene 1 (Stille), White River Valley none. Turnovers -- Eastern Greene 11, White River Valley 14. Total fouls -- Eastern Greene 19, White River Valley 23. Fouled out -- Mowery. Technical fouls -- none.