Then he took over lead vocal duties for the night's finale, There Is A Light That Never Goes Out, one of the best-loved songs in the Morrissey/Marr canon and one that prompted a mass singalong.
Marr's performance was worth the wait. He'd been due to play in February before postponing a string of dates due to family illness.
It's fair to say he's aged better than most of his audience, many of whom are now balding and paunchy, some 30 years after The Smiths changed the face of British indie rock.
At 51, Marr still looks every inch the rock star; lean, with a fine head of hair and the ability to pull off the kind of guitar-throwing pose that would look silly coming from anyone without his mesmerising dexterity.
Like most Mancunians, he's an engaging frontman - somewhere between Guy Garvey's storytelling and Noel Gallagher's super-dry detachment.
The crowd took a while to warm up - middle-aged blokes don't frug all that often, after all. But after an opening salvo of the best tracks from his solo albums The Messenger and Playland punctuated by The Smith's Stop Me ..., things picked up with the white funk of The Headmaster Ritual.
Despite the strength of the best of his solo material, inevitably The Smiths' tracks got the best reception - Bigmouth Strikes Again, How Soon is Now and then Please, Please, Please, Let Me Get What I Want to start the encore.
Getting Away With It - the big track from Electronic, the so-called supergroup Marr formed with New Order's Bernard Sumner, was introduced as a "disco song" from Manchester and revived hazy memories of that city's Hacienda club, but seemed to throw some of the Auckland audience.
Finn's appearance, however, ensured the night ended on a high, with Marr promising to return next year.
