The club's record goalscorer has returned to the north-east as manager with the task of keeping them up.
"I love this club and realise they are in a very bad position and have been give the opportunity to do something about it," Shearer told a packed news conference at St James' Park on Thursday.
"I feel the pain that the fans are going through...but I wouldn't be sat here if I didn't think there was enough quality in that squad. The quality is there, they just need the confidence.
"The fans know they will get 100 percent, 24-hours-a-day for the next eight games. I hope that will be good enough because it would sadden me and thousands of supporters if we were in the Championship. They don't deserve that, they deserve better."
"Shearer said he agreed to take on the short-term role on Sunday, having been given an eight-week sabbatical from his Match of the Day pundit role by the BBC, and completed contract details on Wednesday night.
"I spoke to the players and staff this morning and the training was superb," he said.
"They've set a standard we want to keep to and I said after training that if they kept that standard up then we'll be OK.
"I've watched Newcastle in the last few months and it didn't seem as if they were enjoying their football. But they did this morning and we need to transfer that into Saturday's game."
FIRST GAME
Shearer's first game in charge is at home to Chelsea and with time running out and the club third-last in the standings, he said they had to hit the ground running and get something from the match.
"I think it's a great game for us," said Shearer, who repeatedly insisted that his tenure was for eight games only, after which he hoped Joe Kinnear would return to the manager's role having recovered from heart surgery.
Shearer has no managerial experience and said that was why he brought in former Crystal Palace, Charlton Athletic, Coventry City and Queens Park Rangers manager Iain Dowie as his number two.
"Iain's an experienced manager and he will tell me if he thinks I'm getting it wrong," he said.
"I felt it was important to bring him in, to give it a fresh look."
NEWS: Shearer status on the line, warns Waddle
NEWCASTLE FANS! Check FourFourTwo.com’s ever-expandinginterviews archivefor more stuff to read:
Web Exclusives Les Ferdinand
Q&A Joey Barton
One on One Michael Owen, Kevin Keegan, Les Ferdinand, Faustino Asprilla
Boy's A Bit Special Steven Taylor, Danny Guthrie
‘He instantly popped into our ratings as one of the best U21 midfielders in Europe. The impressive thing is Slot has made him into more of a no.6' Inside Ryan Gravenberch's transformation at Liverpool
‘I don’t think Liverpool would look at Ollie Watkins, a striker isn’t a pressing issue for them – it’s Arsenal who need one’ Former Reds star explains why his old club don’t need an out-and-out forward this summer
