Who: Vampire Weekend

Where and when: Pyramid stage, Friday 6.30pm.

Dress code: You know Vampire Weekend – preppy, right? Well, think again as Ezra Koenig bounds onstage in customary attire, but with two buttons undone on his pressed plaid shirt! Elsewhere, drummer Chris Tomson wears a vest with the American flag on it and Rostam Batmanglij sports a psychedelic sweatshirt.

What happened: Returning to the festival two years after their debut and with another album under their belt, Vampire Weekend have graduated to main-stage status. They are polite to the audience, and witty too. But there's still a sense that this isn't quite enough to hold a festival crowd's attention for a full hour.

Who's watching: Not nearly as many as were watching Snoop Dogg an hour earlier. It's by no means a thin crowd, but it's not always possible to distinguish fans from sunbathers and my suspicion is there are more of the latter. The crowd certainly isn't particularly animated and seem only infrequently to want to sing along. Given the frequent complexity of Vampire Weekend's lyrics, that's perhaps not too surprising.

High point: A Punk, as ever, was a stand-out moment, as were the flashing disco lights that appeared where the eyes should be on a massive reproduction of the Contra album cover. Top marks, however, go to a rather transcendent and wonderful version of Giving Up the Gun, which extends beyond it's recorded length to shift from refined pop into a house workout. Just as it does so, the sun dips behind the Pyramid stage.

Low point: Horchata and Californian English were among the songs from Contra that failed to elicit much response from the crowd. They're new of course, but they're also a bit shy of a tune.

In a tweet: Smart Americans bring dose of east coast intellecto-rock to hammered, partly grateful Glasto-ites.