text: Aided by dancers, confetti cannons and a man in a mirrored suit, the Canadian band revived revellers' spirits with a series of arms-aloft anthems.
  "In a lifetime of pretty much impossible things that have happened to our band, this is the highlight," said frontman Win Butler.
  Earlier, every stage at the event was closed after lightning struck ground.
  Dance act Rudimental were escorted off the main stage mid-set, and had to abandon their planned encore - Feel The Love, with guest vocalist John Newman.
  "We're quite upset," musician Amir Amor told the BBC, "but we had a great time anyway".
  Metallica's Lars Ulrich was flying into the site by helicopter as the storm descended.
  "It was kind of frightening," he said.
  "When we landed, all the people picking us up were going, 'we didn't expect you were going to fly in this weather'.
  "But the pilot didn't say anything about that. We saw the lightning up there. I thought it was pyrotechnics for Arcade Fire."
  The thunderstorm heralded a brief but torrential downpour, and the power cut took BBC coverage off the air.
  Music resumed on the main stage at 19:00 BST with Lily Allen, who dedicated an expletive-laden song to FIFA president Sepp Blatter.
  Other performers on Friday included Blondie, who proved so popular it became impossible to enter or leave The Other Stage at lunchtime, and Paolo Nutini, whose soulful ballads were a fitting soundtrack as dusk fell over Somerset.
  Sophie Ellis-Bextor sneaked some disco into her set at the largely-acoustic Avalon Stage, while the pulsing synthpop of Glaswegian band Chvrches made for a steamy atmosphere in the John Peel tent as fans danced off the downpour.
  Arcade Fire took to the stage shortly after 22:00 BST, their arrival heralded by a man dressed from head-to-toe in a mirrored suit.
  Bravely, considering the weather conditions, the 12-piece band were largely dressed in white, but if they were worried about laundry bills, it didn't show.
  They  threw themselves around the stage, thrashing and spinning as though plagued by a swarm of invisible bees, each member switching instruments between - and often during - songs.
  As well as guitars, they played steel drums, xylophones and even a hurdy gurdy.
  Frontman Win Butler made frequent excursions into the audience and, during the song Flashbulb Eyes, plucked a camera from a press photographer and carried it on stage to capture the band's performance.
  The set list was evenly spread across their four albums, with highlights including No Cars Go, Neighborhood #1 (Tunnels) and Rebellion (Lies).
  The group's recurring subject matter of suburban despair and alienation might have seemed like an odd fit for Glastonbury's peace and love ethos, but there is an optimism and belief in humanity at the core of their music.
  Plus, they have really catchy choruses.
  The band's willingness to embrace all walks of life was displayed on Friday night during the song We Exist - about a teenager whose father struggles to accept his sexuality.
  As the opening chords rang out, a troupe of transgender and cross-dressing dancers joined the band onstage.
  "Every one of us is born special and unique," said Butler. "However you are and however you were born, you're perfect."
  The feel-good atmosphere continued throughout the two-hour set - ending with a mass singalong to the band's signature song, Wake Up.
  Speaking to the BBC earlier in the day, the band's guitarist Richard Reed-Parry said they had enjoyed soaking up the Glastonbury atmosphere on Friday.
  "There's a great feeling coming in," he said.
  "It's a nice vibe. There's lots of families.
  "It's not just about massive headlining acts. And it's not going to be a swamp of corporate beer-swilling drunkards.
  "There's rain and there's mud but it's new and it doesn't smell bad yet. It's like, 'oh, this mud smells like grass! It's spring!'"
  The music continues on Saturday with Jake Bugg, Pixies, Clean Bandit and Manic Street Preachers on the bill.
  Among those watching the action will be Hollywood star Bradley Cooper, who told the BBC: "I'm excited to see Metallica and I want to see Jack White and Lana Del Rey."
  Asked if he was put off by the weather, the Hangover star replied: "I love it. I do! But I'm a dumb American - you expect it."
  Glastonbury 2014
target: Arcade Fire brought a party atmosphere to Glastonbury on Friday, hours after an electric storm stopped the festival.