Liverpool vs Arsenal: Andoni Iraola's side must beat the Premier League champions to be in the title race, says Paul Merson

Champions Arsenal head to Anfield with a six-point lead over Liverpool but have not won there in the league since 2012; Andoni Iraola has beaten Mikel Arteta three times in his last four meetings; watch Liverpool vs Arsenal live on Sky Sports this Sunday, kick-off 4.30pm