The Black Cats passed up an opportunity to reduce the gap to Liverpool, the current occupants of eighth place, to just a single point yesterday [Saturday] when they were held 0-0 at the Stadium of Light by bottom-of-the-table Wolves.
Having taken 31 points from the previous 19 league games they had played under Martin O'Neill, the draw capped a run of just two wins in 10, and while that sequence of fixtures includes a win over the Reds and creditable draws with Newcastle, Manchester City and Tottenham, it has taken some of the gloss off a remarkable recovery.
O'Neill admitted a lacklustre performance - and the term is generous - on a day when chairman and owner Ellis Short has congratulated him for bringing top-six form to Wearside had provided something of a reality check.
However, he insisted his team will not be allowed to coast towards the end of the season, and Belgium international Mignolet has little intention of doing so.
The goalkeeper said: "There are still things to play for and everybody wants to get up in the table.
"We would rather end up eighth in the table than being 12th or 13th, so there's still a lot to play for.
"That's the main thing and everybody is thinking the same way in the dressing room."
There was a distinctly end-of-season feel about the game from the off as Sunderland, safe in mid-table, and Wolves, fighting a seemingly futile battle for survival, scrapped out an uneventful 90 minutes in a subdued atmosphere.
The home side should have taken the lead with 16 minutes played when James McClean was played into space inside the box by Stephane Sessegnon, but shot wastefully into the side-netting.
McClean saw Wolves goalkeeper Wayne Hennessey make a fine reaction save to keep out his 73rd-minute header, but not before Sylvan Ebanks-Blake had squandered a glorious opportunity by firing wide from close range at the other end.
In a dramatic conclusion which had little in common with much of the rest of the game, Steven Fletcher forced a vital diving save from Mignolet and Sebastian Larsson scooped Sessegnon's driven cross over the bar from six yards.
Mignolet said: "If you want to win games, you have to score a goal and obviously in the last couple of weeks, it has been tough for us to try to get a goal.
"It's always dangerous if it stays 0-0, things can go either way. Luckily, Wolves didn't score because they could easily have nicked the game as well, which would have been even more disappointing.
"But on the other hand, we have still got things to play for and hopefully, everybody looks forward to next week."
Next week will see O'Neill return to Aston Villa for the first time since his departure from the hotseat there, and he will do so with the first phase of his mission complete, but knowing he has work to do to take the club to where he and Short want it to be.
By contrast, Terry Connor, thrust into the limelight by Mick McCarthy's departure from Molineux nine games ago, will prepare for the visit of Manchester City, 6-1 winners at Norwich yesterday [Saturday], knowing time is running out fast.
The point his side gained at Sunderland was just their second in those nine games - the first came in the north-east too, at Newcastle on February 25 - but it looks likely to prove too little, too late.
Wolves remain eight points adrift of safety despite collecting their first league clean sheet in 31 attempts and may have to win each of their four remaining games if they are to stand any chance of staying up.
To put that into context, they have managed just five victories in their 34 top-flight games to date this season.
However, Connor remains unbowed as he attempts to mastermind an unlikely escape confident that his players will give him everything they have got.
He said: "The first thing is that they are a very honest bunch. They have been brought up that way, that's something we have asked them to do from the time they have come into the club, so they are honest, they are hard-working.
"It's difficult when you are where we are in the league, but it's not impossible."