What becomes John Legend most?

A grand piano, a tuxedo and a love ballad delivered with his dreamy voice.

For 100 minutes Friday night at Mystic Lake Casino showroom, Legend served up stripped-down tuxedo soul. Well, maybe make that silk pajamas, velvet bathrobe and monogrammed slippers soul. The stripped down doesn’t mean X-rated R. Kelly romps. Rather, it refers to the accompaniment — just a string quartet, guitarist and Legend’s own piano instead of his usual full electric band.

It was the right approach because this was unquestionably the best and most intimate of Legend’s many Twin Cities’ headline performances dating to 2005 at the old Quest (now Epic). There was none of the stagey showmanship, the electro-pop trendiness or the rushed, truncated tunes that made him in the past come across like the Johnny Mathis for the ADD set.

No, on Friday, Legend, 35, took it nice and slow — like a lover should and like he advises in his breakthrough hit, “Ordinary People.”

In November at the sold-out State Theatre, the nine-time Grammy winner cruised through 13 songs in the first 35 minutes and 28 by the end of the night. However, one significant thing has happened since then. His ballad “All of Me” soared to No. 1, becoming not only his first pop hit and his biggest mainstream recognition since winning the Grammy for best new artist in 2005, but it became the wedding song of 2014. In fact, Legend performed it last month at the Kim Kardashian/Kanye West nuptials.

Of course, “All of Me” became the encore and camera-phone moment on Friday. Couples cuddled, women without dates swooned and Legend kept it simple — just his creamy voice and a simple piano line, with the crowd singing the second to last chorus.

Legend has this PG make-out music down to a science. His words are simple but sincere — sort of like Smokey Robinson without the poetry — but his melodies are rich, his piano playing complex, his style sophisticated.

He even knows how to set the mood. Eschewing last tour’s videos of flower petals and his own wedding as a backdrop, he instead had five couples sitting on love seats behind him onstage. He asked one couple, married for four years, for advice. The man said “keep it going,” the woman said “love and respect your wife.” Legend, who has been married for nine months, decided to go with the woman’s advice. He clearly knows the right thing to say — or sing — to women.

“Good Morning” was a perfect little wake-up ditty. The almost swingin’ “Caught Up” was not only catchy but contained the mid-song advice from Legend’s dad that lobster and shrimp is the way to a woman’s heart. “So High” was a big, dramatic power ballad with his supple, sexy voice going so high, then so low and soaring again at the end.

There were a couple of missteps on cover songs in the 19-song set. Adding the string section poured unnecessary syrup on Legend’s slow, melancholy interpretation of Bruce Springsteen’s “Dancing in the Dark,” which was more compelling last fall. And, after talking about how his grandmother taught him gospel piano, Legend offered a Simon and Garfunkel-like reading of “Bridge Over Troubled Water.” The introduction seemed to presage the Aretha Franklin gospelly version of “Bridge” but instead we surprisingly got Garfunkel sans Simon.

But why cavil because, overall, Legend proved that he’s an extension of someone else who made his name in the 1960s and ’70s, someone with a similarly self-inflated stage name — John Legend is becoming the Stevie Wonder of the new millennium.