Stuart Taylor says Hamilton's injury crisis took its toll after they were eased aside by Raith Rovers in their final home outing of the season.
The Accies boss knows the display was a big let down for supporters who saw their team fail to register a single shot on target at New Douglas Park.
Rangers loanee Ben Williamson scored for Rovers in either half to inflict a 13th defeat of the season on Accies, who can now only finish as high as sixth in the table going into Friday's final game away to Inverness.
Depleted Accies were missing 12 players through injury, with one isolating.
Among the notable absentees were top scorer Andy Ryan, defender Jamie Hamilton and midfielder Scott Martin - and Taylor insists that was reflected in the performance.
He said: "We are really disappointed today. We spoke about going out and having a really good performance, getting a win in what was the last home game of the season.
"It would have given the supporters a good performance to watch, but it wasn't to be.
"Raith deserved their win.
"I thought we started brightly but after that we were tired. There were a lot of lads out there really struggling, fighting through knocks and bruises as we were last week as well.
"I think the injuries in the last two weeks just showed in the performance with the fatigue that was out there.
"We are massively disappointed.
"There was one player isolating but I think we've got about 12 out injured.
"Basically everyone we didn't see today was out injured."
Accies handed a debut to 16-year-old Sam Nicolson when he replaced David Moyo for the final 10 minutes and Taylor added: "It was great having young Sam making his debut.
"Gowser [17-year-old Adam McGowan] came on as well and got some more minutes under his belt.
"I felt Steve [Lawson] did well in the middle of the pitch as well, but that's the only positives from today."
A trip to the Highlands now awaits and a positive result at Inverness would make sure of a sixth place finish.
However, if things don't go their way and rivals Morton upset second-place Arbroath it would see Accies slip to seventh.
Asked about his approach for next week, Taylor said: "Pride and professionalism should motivate them.
"We are playing for the football club and we need to make sure we finish with sixth place now."
Follow Lanarkshire Live Sport on Twitter via @LanLiveSport, like us on Facebook or find us on Instagram for the latest sports news, pictures and video.
