By Kate Holton and Paul Sandle LONDON (Reuters) - Pay-TV group Sky has agreed to pay 4.2 billion pounds to show 126 live English Premier League matches a season from 2016 to 2019, smashing analysts' forecasts to beat fierce rival BT to the best games. After one of the most high-profile broadcast auctions of recent times, the Premier League said that Sky had won five of the seven rights packages, including the most popular Sunday afternoon matches showing the likes of Manchester United and Arsenal. Premier League Chief Executive Richard Scudamore said he was surprised by how much the matches had fetched, but he noted that the game was the beneficiary of the two media giants using football to draw and retain customers on their platforms for TV and broadband internet. Sky, which is 39 percent-owned by Rupert Murdoch's 21st Century Fox , has built its business around offering exclusive programming such as premium sports and drama to customers who it seeks to tie in to combined telephony and broadband packages. More...