Kingstone Press Championship leaders Leigh had to fight for their 23rd successive victory at Dewsbury.
Paul Rowley’s side eventually came away with a 32-28 win, but had to stave off a startling fightback from the home side who were 22-6 down just before half time.
However, Karl Pryce gave the hosts some hope on the hooter before Dalton Grant and Luke Adamson went over. But Kay completed his hat trick as the final quarter approached, meaning Grant’s late score had little impact on the outcome.
Meanwhile, in Bradford, the second-placed Bulls got the better of third-placed Sheffield with an impressive 46-12 victory on Sunday.
The Bulls were in clinical mood at Odsal, running in eight tries, seven of which were converted by Danny Addy.
Staying in West Yorkshire, London scored six tries to pull off a 32-12 win over Hunslet at the South Leeds Stadium.
Doncaster remain winless after they were beaten 40-6 at Halifax. James Saltonstall got a brace for the former Super League side while Ryan Maneely, Ben Heaton, Ross Divorty, Gareth Potts, Scott Murrell and Tom Saxton also got four-pointers. Pasqualle Dunn offered Doncaster’s response but Paul Cooke’s men remain rooted to the foot of the table, four points adrift of their nearest rivals, Workington.
Finally, Whitehaven produced a last-gasp win as they ran out surprise 24-22 winners over Batley Bulldgos at the Fox’s Biscuits Stadium.
Batley appeared to be heading for the points as the minutes ticked down to half time, but a last-minute try from Sam Brooks brought the visitors level before Grant Gore showed great composure to add the extras and win the game for Haven. A crucial two points which hauls the Cumbrians out of the bottom two.