Their win over Livingston in midweek was followed by a comprehensive victory on Saturday afternoon, with strikers Marley Watkins and Christian Ramirez both scoring doubles, either side of Scott Tanser's strike for the visitors.
That was pleasing for Glass, who said: "I think there's a bit of toughness about the group that they don't get credit for at times.
"The game got a wee bit messy after the goals. (Manager) Jim's (Goodwin) got St Mirren playing good football and they didn't give up on that after going two goals down.
"Our quality in the first half wasn't what it should have been which allowed them to come into it a bit too much, but we were very professional in the second half.
"Getting the third goal so quickly after St Mirren scored shows the character of this group. They felt like they got a bit of a slap and found a way to fix it quickly. They've done that a few times this season."
Saints boss Jim Goodwin refused to give any excuses for his side's defeat, admitting that they were well beaten by the better team on the day.
He said: "I thought for the first four or five minutes we were OK but after that Aberdeen were the better team.
"It's the first game in a number of weeks where I've been able to say 'we were well beaten by the better team'.
"In recent weeks we've been involved in every game and could have won two or three.
"Aberdeen were a real threat all afternoon. Their front four were terrific and we've got to accept we were beaten by the better team.
"The goals we conceded were really poor from our point of view. When we got it back to 2-1, I thought we could stay in the game, but for Aberdeen to get their third so quickly knocked the wind out of the boys' sails.
"It's not for a lack of effort – sometimes in football you play against teams that are better than you and that was the case today."