Key Points:

Cynics might think she was checking out the competition. But as Kylie Minogue danced, waved and clapped along heartily to Alicia Keys' Auckland concert, it was obvious she was just as much of a fan as the 10,000 other people at Vector Arena.

She even stamped her feet in an arena-wide drum roll, demanding an encore.

And when it came - in the form of a funked-up version of No One - she raised her arms in salute to the formidable Keys. The original pop princess bowing down to the modern-day queen of soul.

The experience was surreal. There we were, having watched American Idol winner Jordin Sparks open the night with a surprisingly heartfelt and warm performance, when Kylie slipped into the seat in front of us. In the middle of the grandstand, amidst hundreds of regular punters.

But the night belonged to Keys, who opened proceedings with a headbanging, hip-gyrating performance of Go Ahead, before a Supremes-inspired routine to Teenage Love Affair.

Accompanied by a seven-piece band of multi-instrumentalists and three back-up singers - who brought the house down on their own on more than one occasion - Keys stormed her way through the opening set, pulling out a high-octane energy most bands save for their closing finale.

Just when it seemed she may be about to slow things down, coyly asking the crowd, "Is it alright if I play my piano for you tonight?" she launched into a colourful, fiesta-fied remix of Karma, describing the genre as "Spanish Harlem".

Listening to Keys on the radio, she may come across as a restrained soul singer, but live in concert she is something else.

She breaks down heartbroken piano ballads, turning them into upbeat, funk jams; she high-kicks and booty-shakes better than Beyonce; she delivers rambling, rhythmic introductions to her songs, and ends them with sassy, understated punchlines.

Admittedly, it's all a bit rehearsed. But Keys wouldn't be the first musician to script her crowd dialogues.

Besides, Kylie didn't seem to mind. And neither did the other 10,000 fans who screamed, stomped and begged for a second encore - even after a two-hour show.

It's a hard act to follow. Good luck Kylie.