Stack scored two tries to inspire Workington to an 18-16 win at Batley, while Hull also claimed a brace as Rochdale beat Oxford 54-12.
Both players record the maximum five points towards their respective competition’s Player of the Year award at the end of the season.
The Australian forward crossed in both halves as Town snatched a late victory and condemned the Bulldogs to a sixth straight defeat.
Stack’s angled run saw him open the scoring in the 12th minute, and he also had a hand in Andy Morris’ second half effort, before touching down again four minutes later.
Stack beat a host of Batley defenders on his way to the line to help seal a win that lifts Town into seventh place in the Kingstone Press Championship.
“Jarrad was outstanding,” said Workington joint coach Gary Charlton.
“His defence was absolutely top class, he ran some very good lines and scored a couple of good tries. He led from the front against very good Batley team.”
Hull’s double contributed to Rochdale’s 54-12 victory and pushed Rochdale into the top four.
Hornets coach Ian Talbot said: “Dave was excellent defensively, shutting down quite a bit of what Oxford tried to throw his way, and he chipped in with two well-taken tries as well.
“We’ve missed him in the last couple of games. He’s a big threat on the edge for us. He’s got pace to burn and he keeps running good lines.”
Championship Player of the Year award
Player of the Week Jarrad Stack also moves into contention after collecting a maximum five points.
4 points – Danny Cowling (Doncaster)
3 points – Lee Doran (Whitehaven)
Championship Player of the Year table
1. Mitchell Stringer (15 points)
2. Scott Leatherbarrow (10 points)
Callum Phillips (10 points)
Scott Murrell (10 points)
Championship One Player of the Year award
Oldham’s Jon Ford moves up to joint-fifth place in the Player of the Year rankings after collecting two points for his hat-trick display against North Wales Crusaders. Rochdale’s Dave Hull is in joint-tenth after winning this week’s Player of the Week award, while Ben Hardcastle and James Tutuila climb the table.
2 points – Jon Ford (Oldham)
Championship One Player of the Year table
1. Mike Bishay (10 points)
Stuart Reardon (10 points)
3. Gary Middlehurst (9 points)