The Foxes took the lead after 28 minutes through former Hartlepool player Steve Howard. Matt Oakley made inroads on the right before releasing the frontman into the area and his low angled shot went through goalkeeper Arran Lee-Barrett's legs on its way into the net.
Hartlepool were level four minutes later when top scorer Joel Porter notched his 18th goal of the season from the penalty spot after being tripped by Jack Hobbs on the left side of the area.
In an end-to-end second half, Lee-Barrett saved bravely at the feet of Howard and Matty Fryatt, while at the other end Michael Nelson fired wide of a gaping goal after a home corner.
The table-toppers regained the lead when Howard slotted home a penalty after Lee-Barrett was judged to have brought down Bruno Berner in the 79th minute.
But justice was done at the death when Antony Sweeney crossed from the right and Monkhouse steamed in to volley an unstoppable shot into the roof of the net from 15 yards.