John Mayer's Global Citizen Set Was A Full-Out Jam Fest

The singer went head on into a Grateful Dead hit and rocked out 'Gravity' to the very end.

At the Global Citizen Festival on Saturday night (September 28), Kings of Leon played their hit "Sex on Fire," and Alicia Keys showed all 60,000 attendees how she was a "Girl on Fire." So when it came time for John Mayer to perform at the massive charity concert, he set the crowd ablaze with "Wildfire" just after sunset.

Mayer stood on the fiery red stage, knees bent to allow maximum bouncing and jamming, as he launched into his Paradise Valley track. The keyboards were crystal clear, and when the chorus came around, Central Park clapped along.

The Manhattan skyline rose above the park, and fans packed in, anticipating songs like "Half of My Heart" and "Paper Doll," and he delivered. Mayer didn't cut anything short or alter his jams for the diverse crowd full of Alicia Keys and Elvis Costello fans (Costello and Janelle Monae showed up for surprise performances throughout the night). He kept his songs lengthy, cradling his guitar for robust solos full of high-fretted finger work. A cover of the Grateful Dead's "Goin' Down the Road Feeling Bad" was one such example.

"Waiting on the World to Change" transformed into a falsetto rendition of Marvin Gaye's "Inner City Blues." And the show-ending "Gravity" turned into a park-wide karaoke event. Mayer took a few minutes to jam before concluding the set with a big bass, kick drum conclusion.

Philanthropists, nonprofit leaders and celebrities like Olivia Wilde, and Gerard Butler co-hosted during the night. Stevie Wonder closed out the show and played John Lennon's "Imagine," using his platform to call out lax gun laws.

Did you watch? Tweet out #GlobalCitizen if you were a part of the show — whether online or in New York City!