Warrington Wolves overcame Leigh 24-10 to reach the Challenge Cup semi-finals.
Rio Ngumoha and Mohamed Salah scored as Liverpool beat Fulham 2-0 to go four points clear of sixth.
Willie Peters says there are "things we need to do better" after Hull KR beat York 48-10.
Alex Oxlade-Chamberlain scored the only goal as Celtic beat St Mirren 1-0 to go second in table.
Hearts scored twice from the 87th minute to beat Motherwell 3-1 to open three-point lead at top.
Mohamed Salah returns among five Liverpool changes to face an unchanged Fulham at Anfield.
Mats Wieffer bagged a brace as Brighton won 2-0 at Burnley, who are now 12 points from safety.