Stubbs lost his job after 77 days in charge, a 4-0 Betfred Cup defeat against Aberdeen among four consecutive losses in his final matches.
McInnes felt his team merited credit for that display and Stubbs deserved more time.
However, he has noted Stubbs’ successor, Oran Kearney, going about making his team more difficult to beat in his three games in charge ahead of the Paisley side’s return trip to Pittodrie in the Ladbrokes Premiership.
“Firstly, I’m really disappointed St Mirren felt the need to make a change right away,” McInnes said. “A manager gets the job in the summer. To see a manager lose his job in Alan Stubbs so quickly is ridiculous.
“But they’ve made a change and they had a positive result against Celtic. You can see a pattern of play that they were trying to make themselves difficult to play against and still carry that threat on the counter-attack as they did against Hibs on Saturday and Hibs won the game from a set play.
“They had a sore defeat in between against Hamilton, but I think Oran will be trying to find out as much about his players as he goes along.
“We ran out convincing winners here last time, but we were very good on the day and brought a lot of speed and movement to the game and were clinical with our finishing. Something similar would be nice, but we fully expect a tough game.”
Meanwhile, St Mirren boss Kearney, above, says he is looking for an instant impact from new signing Adam Hammill.
The former Liverpool, Dunfermline and Barnsley winger joined this week on a three-month deal and could make his debut today.
The 30-year-old becomes Kearney’s fourth signing since the Northern Irishman was appointed last month and the former Coleraine boss has not been scared to throw his new recruits straight into action.
Anton Ferdinand lined up against Celtic little more than an hour after clinching his move to Paisley last month, while frontman Simeon Jackson played the full 90 minutes on his debut against Hibernian only days after agreeing his own short-term contract.
Kearney explained he has had to sift through his list of potential targets looking for players fit enough to join Saints’ fight for survival but believes that, in Hammill, he has found another with the legs to contribute.
He said: “We’re a month past the window closing so a lot of players who are unattached possibly haven’t been keeping themselves in good shape. If a player is going to take four or five weeks that’s no good to us.
“If you take Simeon, for example. He’s 31 and when we did his body fats this week he was at 4 per cent. He’s in unbelievable shape so credit to him. He came in straight away and played 90 minutes last week and did fantastically well.
“Adam is the same. He’s worked tremendously hard to keep himself in good shape. He came in this week and breezed through the fitness tests.
“These are the types we’re looking for because we need instant results. We don’t have six weeks to get people up to speed so it’s really important we get these good pros who look after themselves and are ready to hit the ground running.”
Hammill was released by Barnsley in May but a number of potential moves, including one to Australian outfit Perth Glory, failed to materialise. Kearney aims to use the winger’s pent-up angst to the Buddies’ advantage.
He said: “Adam has racked up 300 appearances at Championship level in England. He had a good season last year and was waiting for certain opportunities. He actually turned down quite a few offers but has ended up caught in a quandary without a club. So there’s a wee bit of hurt there. Now he wants to show people what he’s all about. I think this is the perfect platform for him.”