A controversial penalty try to Leeds two minutes from time deprived Bradford of victory in a match they had dominated at the Millennium Stadium.
Ben Jones-Bishop, who had already scored two tries, kicked ahead and was thwarted behind the try-line by Gareth Raynor. After consultation with his video referee, Richard Silverwood, Steve Ganson awarded the four points, Kevin Sinfield converted and Leeds won 32-28.
The Bulls looked a revitalised side in Cardiff and led 28-10 early in the second half, largely thanks to Elliott Whitehead's hat-trick, but Jones-Bishop, Kylie Leuluai and Rob Burrow cut the margin to two points and set up the nail-biting finish.
Earlier in the day, Crusaders, playing on what might be loosely termed their home turf, became the surprise successes of the weekend with an exhilarating 42-12 win over Salford.
The Wrexham-based side, not long out of administration and with several players still awaiting work permits, ran riot after the break, with Lincoln Withers and Michael Witt outstanding.
Salford's afternoon got even worse after the final hooter, with Wayne Godwin sent off for running into a melee and throwing a punch.
On Saturday, Huddersfield were too good for an error-ridden Warrington, winning 28-18 with two solo tries from Danny Brough.
Luke Gale's early double proved instrumental as Harlequins beat the Catalan Dragons 11-4.
Castleford beat Wakefield 40-20 in a match riddled with penalties and the evening only came to life in the last 20 minutes of the final match.
St Helens were trailing Wigan 16-0 but fought back for an unlikely draw. It was a case of Saints saving the day, if not the whole weekend.Reuse content