Mark Chapman introduces highlights from the day's Premier League fixtures, which see Sheffield United host Brighton and Manchester United visit Luton Town.Three of the last four meetings between Sheffield United and Brighton have ended in 1-1 draws, including the fixture on the south coast in November. But the Blades will be desperate for three points in their battle to avoid relegation.Like Sheffield United, Luton Town were promoted from the Championship last season, and today they host Manchester United, who won the reverse fixture at Old Trafford earlier in the campaign.