Sheffield Eagles stayed in pole position but were given a scare by strugglers Hunslet Hawks.
In their last ever-league game at doomed Don Valley Stadium – their home since 1990 – the Eagles trailed 12-0 nil before sealing a 15th straight league win.
Winger Lee Mapels scored a hat-trick for Hawks with his final try salvaging what could be a vital losing bonus point.
Mapels and Andrew Yates put Hunslet ahead before Sheffield took a 16-12 lead into the break through tries from Menzie Yere, Michael Knowles and James Davey.
Mapels reduced the deficit before Davey grabbed his second and then Vinny Finnigan and David March exchanged scores.
Quentin Laulu-Toagagae went over for the home side before Finnigan grabbed his second, leaving Mapels to grab his third of the night for that bonus point.