Siwa's energetic and exciting Quickstep set to "Are You Gonna Be My Girl" by Jet, was a hit with the judges and fans alike.
Hitting the stage in fittingly bright and colorful ensembles, Siwa and her pro partner, Jenna Johnson, delivered an energetic and exciting Quickstep set to "Are You Gonna Be My Girl" by Jet. The pair -- who are the show's first-ever same-sex dance couple -- earned a total of 29 out of 40 for their routine and ended the night on the top of the leaderboard.
Siwa and Johnson spoke with ET's Lauren Zima backstage after the premiere and the young star opened up about how it felt to earn the night's best score.
"It was so cool! I didn't know when it happened!" Siwa recalled. "When Tyra said it was the highest score of the night, I lost it."
The judges had nothing but praise for their routine, and while feedback was rushed to accommodate Monday night's live show, it's clear that even with a small slip-up and the routine loosing some control in the middle, the judges felt that this was the best dance of the night.
And their scores reflected just that. Carrie Ann Inaba gave them an 8, while Bruno Tonioli, Len Goodman and Derek Hough handed out 7s, for a total of 29 out of 40 -- placing the pair firmly at the front of the pack.
As this is the show's first same-sex pairing, Johnson admitted that there was a bit of a learning curve at first, but one they both overcame quickly.
"It was definitely new territory for me, but the second I met JoJo I felt like this was meant to be," Johnson told ET. "The whole process has been so natural so smooth, and now I'm like, 'Do I even remember how to dance with a guy? That's so last year.'"
During their performance, the two got some enthusiastic support from Siwa's girlfriend, Kylie Prew, who was cheering loudly and excitedly from the audience -- and it seemed to really help.
"Ky is literally the best human being in the world," Siwa marveled with a smile. "Having Kai scream for me here just made my heart so happy."
Siwa and Johnson's major moment also earned them a high score and a lot of love from fans too, many of whom were overcome with emotion over the Dance Moms alum's monumental DWTS debut.
"@itsjojosiwa I CRIED! Today was historic! NEW FAN! I'm 50.," one user wrote.
"JoJo Siwa, making history with the lovely Jenna on season 30 with the Quick-Step! Go, JoJo! You killed it! #DWTS #DancingWiththeStars #JoJoSiwa," another fan tweeted.
"This was cool as hell. So glad to see this happen and congrats to jojo siwa for insisting on a same sex partner #dwts," another use said of the history-making dance.
ET's Lauren Zima spoke with the 18-year-old star ahead of the season premiere about making history on the show, where she revealed her plan for manifesting a winning season, from tried and true rehearsing to keeping a few mirrorballs on her.
"I have a lot of mirrorballs on me. I have a lot of little teensy ones every which way. I am manifesting it," Siwa said. "That's what I've been saying all day today."
"[I'm] very driven and also very competitive," she continued. "I obviously want to win. It's in my blood. I love to win but already doing what I did with this show and with this experience and dancing with another female and being the first, I've already won in a way and of course not the mirrorball yet -- hopefully, manifesting -- but everything that's happened so far and the reaction we've already received from the world is just amazing."
Check out more of Siwa's dance moves when Dancing With the Stars airs Monday nights at 8:00 p.m. ET on ABC.