The pair performed a steamy rumba to "Always on My Mind" during Monday's Elvis Week episode. The routine earned Slater, 33, and Donovan, 43, a great deal of praise from judges — and a score of 30 out of 40.
"It felt great. It was such a nice improvement from last week," Donovan told reporters of the judges' positive feedback. "I blacked out, so I don't remember. I'm going to have to watch it because I don't remember. I was starting to hyperventilate right before it."
Slater, in turn, said it's "nice getting to the end, and then getting your comments, and to see all the smiles on the judge's faces, to see Bruno [Tonioli] lying on the judge's desk."
"Everyone was just so gracious and great with their comments and they gave us such good feedback," she continued. "It's a really nice feeling because you really do care what they say, for sure."
But the factor that made Slater and Donovan's routine so praise-worthy was their off-the-charts chemistry.
"We genuinely get on really well. Rehearsals go so quick," the pro dancer said. "We really do get on and have a great chemistry, which made this dance so much easier."
"[There are] a lot of movies I do with a romantic lead [where] you have at least a couple scenes that are intimate scenes, and you're with [someone] who very well be married or that you just met, you're not in a relationship and so you have to create that," Donovan continued. "And luckily, we've had a few weeks of getting to know each other to become friends."
Slater also detailed how they prepared for Monday's sensual routine: "When it's a rumba, people expect passion, people expect that steam and you really have to tell a story."
"We had the best song, in my opinion. I love this version of 'Always on My Mind.' And I honestly believe in Trevor," she continued. "I believe in his dance ability, I know we have this great connection, this great chemistry. I really fought hard to achieve the environment for us to just be ourselves and be expressive."
Added Slater, "I think it was a dance that really needed it, and it felt really good in the moment."
Donovan also noted they wanted their dance to be "technically sound and correct, but we wanted to absolutely hit those moments where it felt like we were going through something together."
Monday's rumba marked a vast improvement for Slater and Donovan. During the reality show's season 31 premiere, the pair received a 21 out of 30 for their rock 'n' roll quickstep to "Dancing with Myself" by Billy Idol.
Going into week 2, Donovan said on the series that he aimed to "show the judges why I should be on top."
Speculation about Slater's "connection" with Donovan comes amid her split from fellow DWTS pro Sasha Farber after four years of marriage.
Farber, 38, is also competing on this season alongside celebrity partner Selma Blair, who brought the crowd — including longtime friend Sarah Michelle Gellar — to tears with her performance on Monday night.
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Dancing with the Stars airs Mondays at 8 p.m. ET/5 p.m. PT on Disney+.