It was bound to happen at some point. Liverpool’s Unbeaten Premier League run ended with a 3-0 defeat to relegation-threatened Watford. As goals from Ismaïla Sarr and Troy Deeney ensured Jürgen Klopp’s men fell five games short of Arsenal’s 2004 ‘invincibles’ record of 49 Premier League games undefeated. A whole 422 days after their last…