Dancing With the Stars Backstage Scoop: Kellie Pickler and Derek Hough "Blindsided" By Len's Harsh Critique!

Exclusive! Plus, Zendaya Coleman sounds off on getting the first perfect score of the ABC competition hit's 16th season

Looks like the ballroom might need a referee!

Things got super tense on Dancing With the Stars Monday night, when Len Goodman got into a heated argument with fellow judges Carrie Ann Inaba and Bruno Tonioli after frontrunners Kellie Pickler and Derek Hough did a paso doble with Tristan MacManus—which Len thought lacked substance.

In fact, things got so heated that Len even cursed at Bruno!

"It was like Clash of the Titans. It was kind of crazy. I felt like Zeus," Derek told us backstage after the show, with Kellie adding, "It was like a tornado in there!"

So why did Derek decide to go with the bold decision to switch up the trio's paso doble, considering Len has come down on him for his boundary-pushing choreography in the past? Funny you should ask...

"I was a little surprised by Len, honestly, because I saw him earlier in the week, and he was like, ‘Hey, why don't you go put a salvador in there and these moves?'" Derek explained to E! News. "Do I put those moves in the routine literally because he said that. So I thought I was going to have an in with Len this week, but, oh no, he blindsided me!"

Still, fans shouldn't expect the pair to play it safe should they live to dance another week, with Derek promising, "We'll make him curse like you've never seen before on television." Kellie quickly amended, "We'll make him cuss happy cuss words!"

But it wasn't all curses and bad scores as Disney starlet Zendaya Coleman and Val Chmerkovskiy earned the first perfect score of the season with Gleb Savchenko during their trio salsa!

"I feel good. I feel like I work every week and I try to deliver a 10-worthy performance every time," Zendaya told us of finally scoring a perfect 30. "I think that's what I go for every week: to get those three 10's, so just until it happened, I was waiting, but I was working hard. I want people to know that every week I work with the intention of getting them!"

As for Len and Bruno's spat, Val said, "It was awesome, actually. It was great to see! It's good to see them be the characters that they are and put on a great show."