Mickael Antoine-Curier gave Accies a first-half lead but Dundee United levelled through sub Andis Shala's first goal in almost a year.
United pushed for a winner but paid the penalty for missing three good chances in the first 45 minutes.
Hamilton - now seven points behind second-bottom St Mirren - are confident they can escape the drop.
They face Hibs on Tuesday and Antoine-Curier said: "I'm disappointed not to get three points. We had chances and losing a late goal was cruel."
Billy Reid said: "We could have lost yet we controlled the first 30 minutes, got into good positions but didn't work their goalkeeper. United created chances so on another day it could have been even worse for us."
In front of a crowd of just 2011 the first opening fell to David Goodwillie in the 12th minute.
He got on the end of Scott Robertson's cross but his header from 10 yards was just wide of the keeper's left post.
Tomas Cerny saved the day after Gavin Skelton's mistake let in Craig Conway. The left winger blasted it from eight yards and the keeper parried.
Reid's men were poor in the final third and wasted possession too often.
The boss looked exasperated on the touchline as most moves broke down. Skelton had a terrific chance from 15 yards but volleyed wildly over.
Peter Houston had his head in his hands when Johnny Russell missed a glorious opportunity in the 21st minute.
Goodwillie fired a clever ball across the six-yard box that left Cerny and Mark McLaughlin stranded. Russell slid in at the back post and only had to angle it over the line. But the ball got stuck under his left foot and rolled out of play.
In the 34th minute United didn't deal with David Elebert's long throw-in and it led to Skelton being clipped inside the box by Prince Buaben.
Antoine-Curier stepped up and stayed calm to send Dusan Pernis the wrong way. Houston was raging with his players for not attacking the throw-in.
He was also angry with the decision to award the spot-kick and said: "Billy complained last week that a soft penalty was given against his side but he won't get a softer one than that."
David Robertson missed a sitter two minutes later when he shot over from three yards.
Hamilton have conceded 11 penalties this season and it was almost 12. Paul Dixon went down when Jim McAlister challenged but the ref was right to wave away United's claims.
Both sides were almost down to 10 men when Antoine-Curier and Prince Buaben tangled and it threatened to become nasty. But it was handled by ref Alan Muir and he booked the players.
Antoine-Curier said: "Buaben grabbed me by the throat. I asked him to grab me off the park if he wanted but he was very quiet off the park. He seemed happy to have the ref 's protection on the park."
Houston went to a back three for the final 20 minutes when he took off Timothy van der Meulen for Shala.
Accies sub Damian Casalinuovo had a chance to score against his old side but from seven yards out he kicked the ground first, fell over and the ball trickled to safety.
McAlister cleared Sean Dillon's overhead kick off the line as United pressed for an equaliser.
In the 82nd minute Dixon let rip from 30 yards and Cerny was forced to dive to his left to parry away for a corner.
From the set-piece the ball broke to Conway and his cross was met by Shala who headed home from seven yards. Cerny pulled off a save from Goodwillie near the end to save a point.