The evening's two sold-out shows also brought a surprise visit from American Idol winner Scotty McCreery and runner-up Lauren Alaina, who were introduced by none other than Underwood, Nashville's resident Idol superstar.
McCreery and Alaina, who co-presented at Wednesday night's CMT Awards, will make their official Opry debut Friday, six years to the day since Underwood's first performance on Nashville's most famous stage.
Earlier Tuesday, Underwood, 28, held her annual fan club party at the Grand Ole Opry, where fans started lining up Monday night for a chance to see country music's leading lady.
Festivities included a 45-minute performance of fan-selected songs, a personal question-and-answer session and her own version of Family Feud – Fan Club Feud. A few lucky ones were even awarded a trip to her concert and backstage passes.
While Underwood will be jetting off to Australia this week, the rest of the country music community will be hunkering down in Nashville for the 40th Annual CMA Music Festival. Among them, Brad Paisley, Keith Urban, Rascal Flatts and Taylor Swift.
Starting in 1972, Fan Fair was 4-day festival aimed at giving fans an opportunity to meet their favorite singers. Now known as CMA Music Festival, the 4-day event – last year, an estimated 65,000 people attended each day – includes more than 100 live shows, fan club parties hosted by the likes of Lady Antebellum and Blake Shelton, autograph signings and more.