However, the Steelmen boss admitted the Buddies fully deserved to get something out of Sunday's clash.
McCall's men had looked set to claim their second win of the Scottish Premier League season as they led through Michael Higdon's early opener deep into stoppage time.
However, St Mirren, who had received a boost in the 88th minute when home defender Shaun Hutchinson was sent off, claimed a share of the spoils when substitute Thomas Reilly bundled the ball into the net after Steven Thompson forced an excellent save from Darren Randolph.
That was a major blow for the hosts, but McCall conceded a draw was the right result.
"I was disappointed for the lads and didn't want to see them around (referee Euan) Norris at the end of the game," he said.
"There's no doubt that St Mirren deserved a share of the points but we're disappointed in the way that it came about.
"Overall we weren't good enough in possession and struggled to keep the ball."
McCall revealed Hutchinson was distraught at his late red card but hopes the 21-year-old will learn from the experience.
Hutchinson received a yellow card for dissent with 10 minutes remaining and was then dismissed for the second time in as many matches when he lunged in on Reilly - much to the anger of the home support.
"Shaun has to learn from his first booking," McCall said. "He took too long to leave the pitch - he's inconsolable in the dressing room."
St Mirren boss Danny Lennon felt his team, who dominated for long spells before grabbing their late leveller, were good value for a point.
"It is a very difficult place to come and this was a very valuable point," he said.
"We can look at Motherwell and aspire to reach the levels of consistency they have in order to qualify for Europe.
"We got off to the worst possible start and that's two weeks in a row we've been punished for brave defending, but the response we got after that was great.
"We certainly deserved something from the game and I was thinking before the end that we would take something from it regardless of the result."