Indeed, the Magpies head coach sent a message out to supporters ahead of the Tyne-Wear derby on Sunday, assuring them that he won't be complacent following Newcastle's 6-2 win over Norwich City.
But it appears an email reached a Sunderland fan by mistake and, suffice to say, he wasn't pleased!
Shearer, though, made light of the situation and took to Twitter with a jokey response.
He must know that secretly you love the toon! https://t.co/okOwUsMFFB— Alan Shearer (@alanshearer) October 22, 2015
All joking aside, it's very difficult indeed to call this Sunday's Tyne-Wear derby.
Sunderland have home advantage and a strong recent derby record working in their favour. Newcastle, meanwhile, have momentum after their convincing victory over the Canaries.
McClaren's men, though, were only convincing going forward, with a gaping defence still there for the taking in the first half.
Will Sam Allardyce have had enough time to sort out his Sunderland side by the time Newcastle visit? Or will the Magpies be among the goals once again to break their recent duck at the Stadium of Light?