And the Highlanders spurned a chance to win it in the final minute when Slade knocked the ball on as he attempted to offload just 15m from the tryline.
The Force entered the match just three points ahead of the last-placed Highlanders, but their third win of the season now lifts them six points clear of the struggling Dunedin-based franchise.
The Highlanders still have four games to play, but they will now need a major form turnaround to avoid finishing last.
The Force will receive an automatic four points next week for their bye, before rounding off their season with home games against the Waratahs and Brumbies.
Genuine highlights were few and far between with both sides turning to the boot in the opening half in their bid to gain crucial field position.
Neither side were able to use the tactic to any great effect, but the Force were rewarded for a series of crisp passes in the 17th minute when five-eighth Sias Ebersohn touched down in the corner.
From that point, it was a penalty kick-off as Hayward and Slade traded blows from the boot.
The Force looked a tad vulnerable when halfback Alby Mathewson was sin-binned in the 61st minute for deliberate offside.
But they managed to hold firm in defence when it mattered most, with a scrambling effort by Kyle Godwin and Ben McCalman denying Ma'a Nonu a try in the 62nd minute.
The Force suffered a blow before the match when winger Nick Cummins was forced out through injury.
Force coach Michael Foley paid tribute to Hayward, who has flourished since taking over the kicking duties.
"He's a very natural rugby player. He's a very skilful player," Foley said.
"To actually come through and be successful (with that kick) is a good thing for him.
"We've had a lot of close losses this year.
"But to get a close win, and to be in that situation where we were playing with 14 men in our own 22, it's fantastic reward for all the work that's gone in."
- AAP
