Motherwell led through an early Sam Foley goal after a promising start but their performance deteriorated as County deservedly won to preserve their Scottish Premiership status with second half goals by Iain Vigurs and Michael Gardyne.
“I couldn’t have asked for a better start it in the game,” Alexander said. “It was a perfect start, good goal but that weakness that’s been with the team all season crept in and we took our foot off the pedal.
"And we’re not good enough to take our foot off the pedal.
"I’ve said to the players there’s a lot of positive stuff to focus on since January (when Alexander arrived at Motherwell). I will keep that in mind because there’s been some real good performances and quality wins and we’ve done the job that we wanted to do.
"But there’s a bad taste in my mouth from today and might actually be something that’s good for me going forward, actually clarify a few things in my mind.
"If we’re going to be up and down mentally, we need to change because professional football is so competitive and you have to have the highest standards every time.
"Your application, your focus and your motivation should never waver and it wavered today without a shadow of a doubt.
"I don’t think the players went out there with the intention of that happening then maybe the early goal let our minds rest easy and we got punished badly for it.
"Coming into the summer we have to understand that we have to be better over the whole course of the season.
"And we need to identify the players that can help us do that.”
Although ’Well dropped a place in the league to eighth after Sunday’s finale, everyone of a Steelmen persuasion would have been delighted with such an outcome last winter as they were struggling near the relegation mire.
Alexander said: “Points at the start of the season are as important as points at the end. Obviously the team did not pick up enough points in the first half of the season, the team was in big trouble.
"And we did great to get out of that and actually really push and have a very good second part of the season. But today is a little reality check.”