Sabrina Carpenter Shines in SNL Debut with 'Espresso' Performance 

Carpenter rocks "Espresso" on Saturday Night Live. 

Stage set like fancy bar, sips martini before performing. 

Dances with backup dancers dressed as bartenders. 

Song is a hit, climbing Billboard charts. 

Fans love performance, praise dancers and Carpenter's energy. 

Musical guest for SNL season finale with Jake Gyllenhaal.