Newcastle will be sweating on the fitness of outstanding young halfback Tyrone Roberts, who suffered a knee injury in their 18-16 win over defending champions Melbourne in last night’s NRL semi-final.

Knights coach Wayne Bennett says Roberts hyper-extended his knee with three minutes remaining and could miss a week.

Newcastle play minor premiers the Sydney Roosters next Saturday night at Allianz Stadium for a place in the NRL grand final against either South Sydney or Manly.