Lollapalooza is big. It's a mile-long walk between the festival's two main stages with 90,000 music lovers filling in the big gap. And on Saturday night, America's biggest-selling artist of the last decade drew what could go down as Lollapalooza's biggest crowd to date to the fest's biggest stage, and still made it feel like it wasn't big enough.

"Holy s---, there is a lotta people here," an astonished Eminem exclaimed after pausing a handful of songs deep into his Lollapalooza debut. The Detroit rapper's set list was big too. After kicking things off with 'Won't Back Down' of his five-time platinum album 'Recovery,' Em charged through two dozen tracks, with the help of hypeman Mr. Porter, that spanned his 13-Grammy-winning discography.

The adrenaline? Also big. For an hour and a half, Marshall Mathers rapped to what felt like the beat of a marching militia. Roughly 10 minutes in, Em had checked off five songs, but the show was only beginning.

"Yo Chicago, how many people ever had beef with their parents?" Em asked the crowd before jumping into 'Cleanin' Out My Closet,' a throwback from 2002's 'The Eminem Show,' where Em raps about his mama. Midway through his set, Em got assists from three special guests, first welcoming his Bad Meets Evil collaborator Royce da 5'9" for two tracks off their recently released EP 'Hell: The Sequel' -- 'Fast Lane' and 'Lighters.' On the latter tune, both rappers got more help from an unannounced Bruno Mars, who donned his trademark fedora and strummed on an acoustic guitar while the crowd held up their fire. And while Em played several tunes that feature female guests like Dido on 'Stan,' Paramore's Hayley Williams on 'Airplanes Pt. II' and Rihanna on 'Love the Way you Lie,' the only added estrogen on stage all night was singer-songwriter Skylar Grey, who came out for her vocals on 'I Need a Doctor.'

"Do you love Nate Dogg like I love Nate Dogg?" Em asked the Chicago crowd before dropping the toker-friendly 'Till I Collapse,' calling it one of his favorite collaborations with the late gangsta rap legend. "This is my first Lollapalooza and I can't think of a better place to relapse," he said putting on his serious acting face and taking a sip from a jug. But instead of getting back on the sauce mid-set, the booze spilled from bullet holes in his hoodie, like a Carrot Top prank. "I guess I'm just not built for that s---," the rapper concluded before asking if instead he could take the crowd to a time when he "used to get fucked up," and sending everyone into a frenzy with 'The Real Slim Shady' and 'Without Me.'

At the end of the very big evening Eminem came out for a surprisingly small encore. Just one song -- 'Lose Yourself.' But in the theme of Eminem's debut Lollapalooza set, it didn't just leave a big lasting impression. It left a huge one.

Eminem Performs 'Love the Way You Lie' at Lollapalooza