The Eagles beat Castleford 32-22 on Saturday while the Broncos struggled to beat Hull KR of the First Division 46-18 at The Stoop yesterday.
The Tigers, who had previously beaten Leeds and Bradford Bulls, were never in front and the game was marred by a free-for-all after Barrie- Jon Mather's second try. Keith Senior floored Mather with a punch, after which the Castleford centre was helped from the field.
Senior was placed on report by the referee and will have his case examined by the Rugby Football League's executive committee this week.
Senior wrapped the Eagles' win with two tries in nine minutes.
The Broncos benefited from their superior fitness as they racked up 28 unanswered points in the second half.
The other Hull side, the Sharks, were no match for Salford at The Willows as the Reds scored seven tries to two in their 41-10 win to move into their second successive Challenge Cup semi-final.
"We were responsible for everything Salford got," Peter Walsh, the Hull coach, said. "With a completion rate of 20 per cent, we would struggle in a pub competition."Reuse content