Latics now have just five games to climb back above Ipswich into second place or face the lottery of the play-offs.
Manager Jewell has been busy picking his players up after the Sunderland defeat, bringing them in for training yesterday in order to regroup ahead of Saturday's visit to Cardiff.
Three points at Ninian Park would send them back into second place over the weekend – Ipswich don't play until Monday night – and help repair some of the confidence which has been damaged in the past few days.
Jewell said: "What I say to the players in the dressing room has to remain there but I have asked them whether they have the mental strength to get over the line.
"If we do have to go through the play-offs we will need that mental strength, although I don't think it is over by a long stretch.
"A lot of what happens will be down to the confidence we have.
"Confidence in football and in life is a funny thing, there is no explanation for it and no one gives it to you – it just happens.
"Over the next five games the players and myself have to show character and determination."
Against Sunderland, Jewell watched his side struggle to create worthwhile openings and they failed to win a single corner.
The manager felt Latics became too anxious as they pushed for an equaliser and in future wants to see more responsibility throughout the team.
He said: "We lost our shape and we can't keep relying on the front two for goals and to steamroll sides.
"I keep talking about taking responsibility, and when you look at our scoring record, Ellington and Roberts have got 40-odd between them, McCulloch has 12, but after that we have to do better."
Ellington has now gone four games without a goal after previously scoring six on the bounce, although Jewell is backing him to regain his scoring form.
He said: "Nathan looked like scoring every time he got the ball during that six-game run but just now the game is looking a bit more difficult for him.
"If he gets one at Cardiff on Saturday I'll bet the Duke will score in every game after that, that is the type of striker he is.
"Again it comes back down to confidence."
Refereeing decisions have been going against Latics in the past three games but it's something Jewell refuses to blame for the dip in form.
He added: "I'm a great believer in making our own luck and things do tend to even themselves out over the course of a season.
"The goal Nottingham Forest scored a couple of weeks ago was yards offside and we feel Sunderland's winner was offside too.
"Last Saturday against West Ham we felt we should have got a penalty, but we can't feel sorry for ourselves.
"Teams who come second and third or miss out promotion are always the unlucky ones, the best team is the luckiest – that is how I see it."