Katy Perry, Koko, London

At a time when rapid rises in the world of pop are commonplace, the career trajectory of Katy Perry has been especially steep. Her breakthrough single, "I Kissed a Girl", was released only last May, but by November she had presented the MTV Europe Music Awards, an event that a year earlier she watched at home.

Now, fresh from winning Best International Female at the Brit Awards barely a fortnight ago, even selling out two nights at Koko in the middle of a European tour doesn't seem that big a deal. When she next arrives on these shores, she will clearly be playing in bigger venues.

There's no doubt she's an impressive pop product – feuds with fellow pop-stars, rumours of high-profile romances and a dress sense that's eye-catching, to say the least, have meant she is rarely out of the headlines. Combine her saucy image with her religious upbringing (she's the daughter of a preacher and her debut album was actually a gospel record) and she would seem a record label's dream.

To be fair to the 24-year-old from Santa Barbara, unlike most pop starlets she has been unafraid to step into the grimy world of touring, honing her live skills on the US punk festival, the Warped Tour. It's likely that there she would have faced a more hostile audience than tonight's crowd, which seems full of teenage girls, many with parents in tow. Camera phones aloft, they greet Perry with screams of "I love you Katy".

From the opener, "Fingerprints", it's a night for high-octane pop-rock songs. Unsurprisingly, it's the singles that are the high points – "Hot N Cold" is the first number to get the crowd singing along, with Perry climbing on to the speaker stack.

Yet, just as on her album One of the Boys, too many of her songs are soft rock by numbers, and when she slows it down even further, the energy starts to ebb away. Fortunately, these moments are kept to a minimum. Also, Perry has the personality and the experience of how to work a crowd that will ensure she's more than just the next Avril Lavigne. She's at her best on songs such as "Ur So Gay", which in spite of its questionable lyrics is a brilliant attack on a former lover – during it she urges all the girls to phone their exes so they can listen.

Although at moments she steers far too close to the middle of the road, the high points more than make up for this. The sense of adulation in the room doubles as, for her encore, she appears wearing a leopard-print catsuit, complete with a tail and pink bow in her hair. Although the subsequent cover of Queen's "Don't Stop Me Now" brings back too many memories of McFly's butchering, the final song – yes, it's "I Kissed a Girl" – truly brings the house down. With its pumping faux-lesbian electro chorus, this is undoubtedly a classic pop song – it proves that if she can stay away from the soft rock ballads, her trajectory won't start dipping anytime soon.