Indeed Shearer says the clash at St James' Park will be career defining for anyone involved in the match.
The North East duo currently fill two of the three relegation spots in the Premier League and the chances of either getting out is looking less and less likely.
And both clubs know that anything other than victory next Monday will just about confirm their relegation to the Championship, a division neither has been in for more than a decade.
"The game at Anfield was never going to seal our fate, but the Middlesbrough match is a massive one, not just for us but for them as well," Shearer said in the Daily Telegraph.
"It will go a long way to deciding the outcome of the relegation fight for both of us.
"There's no question that it is the biggest game of my Newcastle career.
"It's the biggest game in the Newcastle career of anyone who is connected to the club at the moment."