Nelson went down 2-0 at Garstang on Saturday in a game which saw four players sent off.
Garstang made it four consecutive victories as they saw off the Admirals at the Riverside.
The first half was quite even in overall play but the clear chances fell to Garstang.
Both Coar brothers had efforts well saved from close range, and Sam Maddox saw a free kick hit the top of the Nelson bar.
The Blues were restricted to speculative efforts which never troubled Will Kitchen.
The game changed in a six-minute spell during the second half when Dave Rossall appeared to barge into the back of a Nelson forward, who was going away from goal.
The referee adjudged this to be a foul, and awarded a spot kick for the visitors, but Kitchen pushed away Harvey Macadam’s effort.
On 60 minutes, Nelson keeper Ben Parkinson spilled a goalbound effort, and Alan Coar followed up to try and turn home the rebound.
In doing so, Coar was adjudged to have fouled Parkinson, and was shown a second yellow card.
Rossall marshalled the home defence superbly as, despite being down to 10 men, the Riversiders looked like the team who were going to break the deadlock.
The lead came on 76 minutes when Jonny Hothersall fed Josh O’Neill, whose cross was half-blocked and fell kindly to Ric Coar, who was on the spot to tap home from close range.
The speed and direct running from O’Neill and Griffiths caused the visitors no end of problems, which freed up space for Hothersall to get the ball in dangerous positions.
With three minutes left, one of those attacks saw Hothersall barged to the ground and a penalty awarded.
Hothersall stepped up and sent the keeper the wrong way as Garstang took an unassailable lead.
O’Neill had been on the receiving end of some robust challenges and, late on, one of those saw him on the ground and surrounded by Nelson players.
There was a resulting melee with pushing and shoving and, after order was restored, a number of players and officials from both sides received their marching orders.
O’Neill was sent off for Garstang, with Charlie Lloyd and James Wolfenden dismissed for Nelson.
Boss Andy Harrison said: “Best team won on the day.
“I think today was the first game of the season where we didn’t create a single chance of note, bar a missed penalty.
“Another one we swiftly move on from.”
Nelson host Pilkington on Saturday, kick-off 3 p.m., and Holker Old Boys on Tuesday night, kick-off 7-45 p.m.