Less than a week after announcing that lingering effects of double pneumonia would force him to cancel his February tour dates, Merle Haggard returned to the stage Saturday at the Mandalay Bay Ballroom in Las Vegas to prove he’s got plenty of lung power left.

Joining Haggard on stage for about 30 minutes was country superstar Toby Keith, who performed the classics “Sing Me Back Home” and “Rambling Fever” with his hero, according to Haggard’s spokeswoman, who noted the singer intends to perform Wednesday in Santa Rosa, Thursday in Beverly Hills (with Kris Kristofferson) and Saturday in Oakland.