Rian Bray was shown two yellow cards within fifteen minutes as the hosts were reduced to ten men before the half-hour mark.
However, the Beavers entered the break in-front after former Clarets striker Chris Dickson executed a magnificent lob over debut goalkeeper Nathan McDonald.
The Clarets never really looked like equalising throughout the second half as the hosts produced a resolute defensive performance, but Murphy made no mistake by slotting home from the penalty spot to salvage a point.
In a relatively open beginning to the match, City came closest to opening the scoring first. Scott Fenwick picked out Chris Whelpdale’s darting run inside the area, but the midfielder’s weak header was easily caught by Tom Lovelock.
A minute later Dickson had a chance for the Beavers, but he shot well over after cutting inside on the edge of the box.
Bray’s late tackle on Murphy on the tenth minute saw the Beavers midfielder enter the book, a tackle he undoubtedly rued making fifteen minutes later.
The Clarets main attacking threat seemed to appear through quick counter-attacks but, despite the numerous deliveries into the danger zone, City were unable to convert.
City broke forward quickly following a Hampton free-kick, Joe Anderson placed a first-time left-wing cross into the area, but Lovelock claimed the delivery.
Murphy’s quick feet on the left wing allowed him to skip past Oliver Sprague. Having poked the ball towards Fenwick, Michael Corcoran acted swiftly to clear the danger off the line.
However, it looked as though it could be a positive day for City when Bray was given his marching orders for a second bookable offence after 25 minutes.
Following a foul on Tom Wraight, Anderson stepped up to recreate his freekick goal against Hungerford Town a week ago, but his dead-ball effort was always rising and went well over the bar.
Having already been reduced to ten men, the hosts were forced to make an early change when Sprague suffered a hamstring injury and was forced to make way for Nathan Mavila.
Dickson tested McDonald with five minutes of the half remaining but, after skipping over a late tackle inside the area, the former Claret had his tame effort held well by the City shot-stopper.
City were forced to play first half stoppage time with ten men as Murphy received treatment following a nasty head injury.
With moments of the half remaining, the Clarets were unable to run the clock down as Dickson latched onto a loose ball in-front of the City defence and instinctively lobbed McDonald to provide the Beavers with the lead at the break.
Anderson’s rising effort after the break provided a glimpse of attacking intent, but defensive fatalities remained as Omozusi’s back-pass almost provided Dickson with his second goal, although McDonald reacted quickly to deal with the danger.
As the game approached the hour-mark, City boss Rod Stringer looked to change things with a double substitution; Shaun Batt and Jazzi Barnum-Bobb came on in place of Anthony Church and Chris Whelpdale.
City came close when Reason opted to pass a quick corner to Anderson, the full-back picked out Tom Wraight at the far post but the winger’s header was straight at Lovelock.
With a final throw of the dice, Stringer searched for a creative element as he replaced Fenwick with Taylor Miles with sixteen minutes remaining.
Murphy’s deft flick of a corner found Swaine at the far post, but the tall defender could not keep his shot on target as it cannoned wide.
Batt should have levelled the scores when he raced through-on-goal on 78 minutes, but the substitute had his low shot saved well by Lovelock.
However, the Clarets were awarded a penalty right at the death when referee Robert Massey-Ellis deemed a right-wing cross to have been handled in the area. Murphy stepped up and kept his composure to strike low past Lovelock and steal a point to bring home to Essex.
Hampton & Richmond Borough:
1. Tom Lovelock
2. Dan Bowry
3. Oliver Sprague
4. Ricky Wellard
5. Rian Bray
6. Michael Corcoran
7. Zak Joseph
8. Casey Maclaren
9. Craig Dundas
10. Chris Dickson
11. Rhys Murrell-Williamson
12. Simon Downer
14. Tyrell Miller-Rodney
15. Nathan Mavilla
16. Daniel Uchechi
17. Matty Whichelow
1. Nathan McDonald
3. Elliot Omozusi
5. Michael Spillane
6. Rob Swaine
8. Anthony Church
9. Scott Fenwick
10. Jai Reason
11. Tom Wraight
13. Joe Anderson
18. Chris Whelpdale
19. Scott Fenwick
2. Jazzi Barnum-Bobb (58', on for Anthony Church)
4. Max Porter
12. Taylor Miles (74', on for Scott Fenwick)
14. Mark Haines
17. Shaun Batt (58', on for Chris Whelpdale)
Hampton & Richmond Borough: Chris Dickson (45').
Chelmsford City: Rhys Murphy (90' P).
Hampton & Richmond Borough: Rian Bray (10', 25').
Chelmsford City: Michael Spillane (84).
Hampton & Richmond Borough: Rian Bray (25).
Chelmsford City: None.
Half Time: Hampton & Richmond Borough 1-0 Chelmsford City
Full Time: Hampton & Richmond Borough 1-1 Chelmsford City