The 16-year-old country singer has been a frontrunner all throughout season 24.
During the first live show of the season, Ruby took the stage to perform an impressive rendition of Reba's 1990 single "You Lie," which her coach said during rehearsals that she performed even better than she did.
And the live performance was even better, bringing both Reba and fellow coach Gwen Stefani to tears.
"You blew it out of the water," she said as she wiped away tears. "Gwen and I are bawling!"
"There hasn't been a time that you performed on this show that I haven't gotten goosebumps," Niall Horan agreed. "You are insane!"
ET spoke with the coaches on the red carpet ahead of the season's first live show, and all of them marveled at the range of talent they've seen on the show this year.
"The talent this year has just been like, across the board -- all of our teams are pretty insane," Niall raved. "The voices that I have this year are just like, some of the best singers I've ever heard."
John agreed, saying, "The depth of the talent this season is better than I've ever seen it on this show since I've been here."
"This is my eighth season and I've never seen just this level of quality across the board," he continued. "I'm so impressed with our artists this year."
"I have some amazing singers, and I think it's just gonna come down to at this point people start to fall in love with not just the voice, but the person as well," Gwen shared. "It's ridiculous this season. I know we say that every season and it always feels like that, but this one has a particularly tall order."
"I really couldn't tell you [who might win]," Reba agreed.
The Voice airs Mondays at 8 p.m. PT/ET and Tuesdays at 9 p.m. PT/ET on NBC.