Tinie Tempah, Koko, London

When Tinie Tempah announced to the crowd: "This is the best city in the world by far," before ripping into his hit song "Frisky", the place was reverberating with cheering people bouncing around in excitement.

For the most part, however, the south Londoner's performance was a display of contradictions, ranging from amusing to disappointing. Unquestionably, Tempah is the consummate showman; you cannot fault the genuine enjoyment he seems to gain from performing.

His incredible year has seen him score a chart-topping single, "Pass Out", a No 1 album with his debut, Disc-Overy, culminating in a double Mobo win earlier this month. His endless energy and cheery smile show that he has taken his meteoric rise comfortably. Yet his stage banter conveyed a sense of uneasiness with his sudden fame, and there is always the feeling that he's trying to keep it real. "I'm so happy to be back in my home city... I can go to Nandos down the road," he chortled.

It felt like a teen disco: indeed, when 21-year-old Tempah took a straw poll, the result showed that most of the audience was born in the 1990s. It didn't add to his hip-hop credibility that some of his best album tracks, "Obsession" and "Let Go" were accepted without reaction by the crowd. Koko only rocked when he played his chart numbers.

Somehow, he turned the gig into a classroom, asking the audience to take away the important lesson of being able to let go of an obsession. Yes, he admitted, the fame and money are good, but for him, "It's about the music." Strange, then, that he should follow this by asking the crowd to buy his record or a TT T-shirt.

His vocal performances could have brought the concert back from the brink, but when a group of X Factor contestants joined him onstage for his dance track with Swedish House Mafia, "Miami 2 Ibiza", the show became a theatre of the absurd rather than a showcase of the freshest urban talent.