The songwriting duo then introduced former Eagle, Bernie Leadon, for a rendition of Train Leaves Here This Morning.
The musicians met four decades ago and Henley joked: "Bernie is still wearing the same shirt."
This was a much more low-key start to previous Eagles tours.
Gone were the smart business suits: checked cowboy shirts and jeans were back in vogue with the Californian crooners.
The crowd began to find its voice during third number Peaceful Easy Feeling and sang along with every word.
Song by song the rest of the group appeared.
Joe Walsh delighted fans with his trademark sizzling guitar licks on a stripped-down version of Witchy Woman.
Frey and Henley narrated highlights from the band's glittering past on videos on giant screens.
But as ever, it was classic song after classic song that did most of the talking.
Henley seemed strained at times on vocals during some of the pared-down arrangements in the early part of the concert.
But the audience soon took over and seemed to know just about every word as the Eagles launched into a lengthy string of worldwide hits.
Tequila Sunrise, Already Gone, The Best of My Love, Lyin' Eyes, One of These Nights, Take It to the Limit ... the country rock anthems kept coming.
The second half showcased the latter period and slightly harder-edged, guitar-fuelled side to the band's career.
It opened with Walsh belting out a moving version of Pretty Maids All in a Row. This was followed by crowd pleasers New Kid in Town, Heartache Tonight and The Long Run.
Frey thanked fans for "being so attentive during the quieter songs, but now it was time to rock".
Fans took this as the cue to get on their feet and start dancing during Heartache Tonight, as Walsh blazed away on soaring slide guitar.
Suddenly the party was on.
It continues tonight with the band's second Mt Smart show - and despite the threat of Cyclone Pam, the tickets say the band plays "rain or shine".
Pair take it easy
There was no Heartache Tonight at the Eagles' soldout Auckland gig for the music fan whose sad love story sparked an internet auction sensation.
A Rotorua woman calling herself "Kazza" had bought a concert ticket as a gift for her then-partner's birthday.
But, according to her Trade Me listing, the 62-year-old grandmother was left as The Girl from Yesterday after he ran off with another woman.
Her auction attracted 42,000 views and was eventually won by a Hamilton man who paid $300 for the ticket. "He is very handsome," she beamed. "He looks like a KGB man and that makes me feel very safe."
The pair watched the concert from the South Stand.
Murray, who would only admit to being in his 50s, said he was immediately taken with Kazza. "The first thing I noticed was the big grin on her face.
"She has a fantastic personality and is full of great stories," he said.
"We hit it off straight away and I am definitely keen to get to know her better and see her again.
"This has been a great way to meet a lovely new friend."
