Is it any wonder Derek Hough is a five-time Mirror Ball winner? He elevates his dancers to such a high level -- and Alexa Penavega was the benefactor of that during "Dancing With the Stars" Season 21 switch-up week.

Alexa and Derek danced an incredible tango to "Pompeii" by Bastille, which was a huge comeback for the actress after forgetting her routine a week ago.

RELATED: Alexa and Carlos Penavega do dueling jives on 'DWTS'

The judges were over the moon -- and gave Alexa the first perfect score of the season, four 10s for a total of 40. It bested her husband Carlos' 39 out of 40 for his quickstep.

After the performance, Carrie Ann Inaba gave her a standing ovation and called it "a revolution."

"A natural, authentic, raw person and that's what we saw tonight," says Julianne Hough. Guest judge Maks Chmerkovskiy praised her getting out of her own head and letting loose, while Bruno Tonioli calls it "an utter and complete victory."

Posted by:Andrea Reiher

TV critic by way of law school, Andrea Reiher enjoys everything from highbrow drama to clever comedy to the best reality TV has to offer. Her TV heroes include CJ Cregg, Spencer Hastings, Diane Lockhart, Juliet O'Hara and Buffy Summers. TV words to live by: "I'm a slayer, ask me how."