"I wake up every morning," said Justin Timberlake, with the reverence of one who has just discovered the sun also rises every morning, "and I can't believe this is my job: it's just so f****** cool."

It's curious he should feel that way, having been groomed for pop stardom since he and former squeeze Britney Spears were in the Mickey Mouse Club programme together as prepubescents.

Even so, Timberlake could have fallen by the wayside after being just another member of just another boy band, *NSYNC. Instead, a succession of smart choices means he now finds himself a global superstar. Clearly things are going well.

There were moments - lots of them in fact - during this all-singing, all-dancing extravaganza where Timberlake justified the brouhaha. The supertaut Sexy-back featured his producer Timbaland and was a stirring, sex-charged spectacle, while a stripped down What Goes Around showed that sometimes he has the songs too.

While the show soared, Timberlake was the ringmaster of a sense-tickling jamboree and when Cry Me A River built from humble beginnings into an all-out, kitchen sink extravaganza, he even had a spark of genius, albeit one which owed much to the staging, dancing and sound of Michael Jackson and a Prince-like desire to be unspeakably funky.

Sometimes though, it all went awry. The setting hardly helped. Performing in the round was always going to cause sound difficulties, but the promised visual coup was ruined by sheets of what appeared to be net curtain, similar to that found in Tyneside council houses.

They descended intermittently and were too see-through to display the projections properly, but too dense to avoid making every seat in the arena a restricted view. Indeed, when Timberlake sang the confessional ballad Losing My Way encircled by the stuff and its lyric asked, "can anybody out there see me?", the resounding answer was "not really, no".

For all his filming himself with his mobile phone, Timberlake clearly craved respect, hence his need to repeatedly stop singing and dancing (a combination which, curiously, never left him short of breath) to play a guitar or a suspiciously battered piano, although the presence of three (three!) other keyboardists on Sexy Ladies ensured it was unclear just how much the star was doing.

When, first, he lauded "our troops fighting for our freedom" - inspiring the second cheer for the Iraq war this week after Prince Harry's words at the Diana concert - and, then, the encore, (Another Song) All Over Again, hinted at Elton John-style balladry, Timberlake seemed old for his 26 years. Clearly, he's going to be doing his "cool" job for some time yet.

• Justin Timberlake plays the O2 Arena tonight and 7, 8, 10 July. (0870 534 4444)