There’s no overstating the extent to which country superstar Tim McGraw is able to get by on muscles and charm.

If you’d closed your eyes Saturday night at Jiffy Lube Live, you’d have sworn that McGraw had handed his microphone to a fan in the front row, so woefully off-pitch were his vocals.

And when you opened them, chances were you’d find McGraw had stopped singing and assumed an acre-wide, come-worship-me pose. A surprisingly decent movie actor (“The Blind Side,” “Country Strong”), McGraw need only play one role onstage: Badass hunk.

Whether or not he’s phoning it in, McGraw is obviously doing something right: With two decades of touring and hit-making under his shiny, paperback-size belt buckle, McGraw has no trouble packing them in.

He kicked off Saturday’s two-hour set at the outer fringe of the Lube’s pavilion to give some face-time to the folks on the lawn, delivering the stomping hits “Something Like That” and “Where the Green Grass Grows.”

After high-fiving his way back to the main stage, McGraw settled into syrupy ballads like “Just to See You Smile” and “Please Remember Me,” plus a so-so new song, “Right Back At Ya,” that awkwardly attempts to straddle the gap between country music and adult contemporary radio-programming formats.

This interlude culminated in a curious, and somewhat bold, cover of the Commodores’ “Sail On.” Let it be known: Tim McGraw loves him some Lionel Richie.

Duets with warm-up acts the Band Perry and a tipsy-seeming Luke Bryan (on “Can’t Be Really Gone” and “Back When,” respectively) gave McGraw a much-needed goosing — but this fresh steam quickly evaporated as McGraw and his bandmates stumbled through three false starts on the new ballad “Better Than I Used to Be.”

“Thanks for sticking with us on that one,” said a sheepish McGraw.

The back quarter of the show hummed along at a breezier clip, as McGraw bundled together a tranche of such recent hits as “Felt Good on My Lips” and “Southern Voice,” the mid-’90s smash “I Like It, I Love It” and “Live Like You Were Dying,” the poignant tribute to McGraw’s late baseball-hurling father.

However the blossoming acting career pans out, McGraw seems in no danger of losing his night job.