Hull FC recorded their second victory in four days to set up a Challenge Cup quarter-final with Wigan Warriors, after eliminating Castleford in a game which served as a reminder of the physical demands rugby league players are set to endure over the remainder of this season. With this the first real opportunity to see how multiple games a week would affect the sport’s players, who are being forced to endure a domestic schedule like no other before to ensure the season is completed, it was Hull who emerged through a contest where the effects of playing as recently as Thursday for both were brutally evident. They finished with just one fit interchange after injuries to three of their key players – Jamie Shaul, Ratu Naulago and Albert Kelly. Two of those were muscle injuries, perhaps a grim indicator of what may become a recurring theme in the coming weeks and months as both Super League and the Challenge Cup play to some sort of conclusion. Castleford also lost two players to injuries here, and both squads looked drained in the closing moments as Hull navigated their way to a victory they probably deserved. Leading 18-6 at half-time after two tries from Carlos Tuimavave and another for Kelly, they never really looked in danger throughout the second half. “We’d used all our interchanges with 12 minutes left, and the guys left out there were playing with injuries,” Hull’s coach, Andy Last, said. “The players deserve all the credit for what they’re doing.” Castleford had levelled the game at 6-6 earlier thanks to George Griffin’s try, but a second defeat in four days always seemed likely here. “I’m telling you now, this is going to get more difficult,” Daryl Powell, the Castleford coach, said. “Both teams are absolutely busted. The blokes on the field at the end were just laid on the floor because they’ve got nothing left. I just think it’s asking a bit too much.” He lost Sosaia Feki and Grant Millington to injuries, and they were always a fraction off the pace here. When Naulago’s try shortly after half-time made it 24-6, Castleford did briefly threaten a comeback courtesy of tries from Oliver Holmes and Peter Mata’utia. But Hull’s injury-hit side recovered well to regain control of the contest. They closed out victory in a composed manner, courtesy of two penalties and a late drop goal from Jake Connor in the final minutes.