Britney Spears is back on tour and you better believe she's here to work

You better work, Brit.

The Beatles said "Let it Be," Bruce Springsteen was "Born to Run," Gloria Gaynor preached "I Will Survive," and Drake has his philosophizing "Motto."

But it was Britney Spears who inspired us to work.

Five years after "Work B**ch" became #goals, and a little more than 19 after her first headlining tour, Britney's back and working harder than ever. This summer, she's taking her "Piece of Me" show from the Vegas strip to more than a dozen cities in North America, Europe and the U.K.

The tour comes after an immensely successful stint in Sin City, where her "Britney: Piece of Me" show earned $140 million after four years and 250 ticketed performances. Last year, she commanded the highest ticket price of any Vegas production show -- $855 for all the VIP treatment. It became one of the most successful Vegas residencies of all time, particularly with a much-sought-after younger crowd.

That type of success isn't built on nostalgia alone. The pop icon works like she's made those famous 2013 lyrics her personal ethos.

Her first tour stop Thursday night at the MGM National Harbor Casino outside of Washington, D.C., made a Britney-themed Soul Cycle class seem like a walk in the park. The sold-out 90-minute show was a non-stop ride -- a whirlwind of turns and squats and her signature arm waves.

She covered 25 songs, all hits, with only brief interludes that were surprisingly entertaining and could have lasted longer to give the 36-year-old more of a break. At times she looked like a marathoner, obviously conserving energy on a downhill segment before bursting into a complicated sequence.

As fans filtered out of the 3,000 seat auditorium -- an intimate setting which made her performance feel like it was broadcast in HD compared with those old arena tours -- her history as a workhorse became even more clear. At the Live in the Lobby Bar afterparty, a cover singer tackled "Lucky," leaving many fans openly lamenting that it hadn't made the real Britney lineup. She simply has too many hits to fit into one show.

Here are the highlights from the opening night:

Work B**ch

The perfect opener, Britney set the stage with her energetic anthem, emerging in a green fur coat that was quickly shed before she got down to business with a smoke-filled floor routine.

...Baby One More Time

Save for a few tweens, no one in the crowd Thursday was that innocent, Britney included. So the decision to avoid the naughty school-girl vibe was wise. Brit came out in wings in front of a red and black screen with a gothic, Tim Burton vibe.

Scream and Shout / Boys

To be a true icon, one must acknowledge the iconic moments, as Britney did Thursday, uttering those three little lines from the beginning of her 2007 song "Gimme More" and Will.i.am.'s 2013 single: It's Britney, (expletive). The medley also got an expert laser and neon treatment, and at the end of the mini set, a quick routine to a Missy Elliot trio that could have been a full segment unto itself.

I'm a Slave 4 U

Another intelligent update? Swapping snakes for a little pole dance. Bondage imagery on the background screen added to the sexy scene without being too much. And a quick take on Migos' "Walk It Talk It" brought the set into 2018.

Freakshow

Who needs gimmicky audience interactions when you can bring an audience member on stage, put them in a leather harness, and have Britney Spears walk them like a dog? No one.

Circus / If U Seek Amy

The overall effect of the stage design, costumes and choreography made this segment one of the best, and put Britney where she belongs at the center of the stage. She's a put-on-a-show kind of girl, after all.

Toxic

In another clever reinterpretation, Brit came out in an apple-red bodysuit with a glowing green jungle background, a sensuous Eve tempting her audience. And they were lovin' it.

WPXI