The Easter Road side were left stunned as Morton clocked up a 3-0 win, leaving them trailing Rangers by eight points with only 11 matches remaining.
But, admitting his players should have capitalised on the chances created early in the game – top scorer Jason Cummings somehow heading wide from only three yards out the clearest of them all – Stubbs bemoaned the goals conceded.
Thomas O’Ware headed the Greenock side into a shock first-half lead and, as Hibs struggled to regain their composure, they were picked off after the interval as Denny Johnstone and Ross Forbes claimed two more for Jim Duffy’s men.
Answering “it might be, it might not be” when asked if the title race was now over, head coach Stubbs – his side having lost just twice in 29 games – said: “We have been eight points behind before and managed to claw it back but there’s obviously less games to go.
“That makes it harder, I am not going to deny that. Obviously, it is a blip for us but I cannot criticise my players too much. I’ve not been in this position a lot of times this season. They’ve had a lot of plaudits but this time we just fell below the standards we have set.
“We made too many individual errors. We had a couple of good chances in probably a 15-minute period, 20 minutes at the most and we did not take them. Then we have given at least two poor goals away when we should do better.
“But you have to credit Morton. When they had their chances they took them.”
Stubbs made seven changes to the side which defeated Alloa at the weekend when he made as many switches, but he was adamant that had no impact on this match, pointing out that the team he fielded was predominantly made up of players who have featured on a regular basis this season.
He said: “I do not think that had anything to do with it whatsoever. If we had been beaten at the weekend people would have looked at the changes then. The team that was out was strong enough to get the result.”
Stubbs also insisted his players have to dust themselves down and be ready to go again when they face Dumbarton on Saturday, pointing out they still have plenty to play for with a League Cup final place assured and into the last eight of the Scottish Cup as well gunning for promotion.
He said: “These things happen in football. It’s a test. When you think everything is really good you do not see a defeat on the horizon, it comes completely out of the blue. It happens to everybody. You have to dust yourselves down, regroup and go again.
“The players are disappointed, I didn’t expect anything less. It was a quiet dressing-room afterwards but they need to understand these things happen. They have done very well up to now.
“We have a lot to play for, this is not one of those results that your season is completely over.
“We are still in two cup competitions and we are still in their with a fighting chance – it just makes it a bit harder for ourselves, that’s all.”