Hamilton boss says it was was a "stupid" mistake which cost them the game against 10-man Kilmarnock.
Greg Kiltie gave the Ayrshire outfit the lead before Hakeen Odoffin levelled for Accies, but Nicke Kabamba's second half strike decided the game.
Eamonn Brophy was shown a straight red for a poor challenge on Scott McMann.
It brings a tough week to a close for Brian Rice's men after a coronavirus scare decimated the squad.
Rice told the BBC : "I thought we started the first 20 minutes poorly and Kilmarnock were well on top.
"It wasn't until we got the goal and they had a man sent off that we took control of the game.
"I told them at half-time the only team that could beat them is yourselves if you do something stupid, and that's exactly what we done for the second goal.
"A stupid pass and we got punished for it, and fair play to Kilmarnock they defended brilliantly and we couldn't break them down.
"The final cross, the final pass wasn't good enough, balls were going into strikers and we weren't holding it up.
"At times we were just keeping the ball for keeping the balls sake. We were trying to work it wide and get at them and it became a bit predictable.
"Quality in the final third and the final pass is something we need to work on."
When asked if the Covid scare had impacted on the result, he added : "Absolutely not, no excuses."
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