The BBC pundit has been discussing the Scottish champions and the Scottish Championship leaders.
Indeed, Sinclair has shown great affection for Celtic over the last few months and sees their rivalry with old foes Rangers as matching one of the world's biggest.
The Gers currently find themselves top of the Scottish Championship and could therefore be in the same division as Celtic once again next campaign.
Of course, many Celtic fans argue that this isn't Rangers and that the old Ibrox outfit are already extinct.
But Sinclair believes the Celtic - Rangers rivalry is still up there in terms of world and British football.
Both Celtic and Rangers won on Saturday afternoon, while Liverpool host Manchester United on Sunday.
It should be an epic encounter and the Reds will finally fancy their chances against United. Louis van Gaal's men look vulnerable and Jurgen Klopp seems a master of the big occasion.
But who will actually come out on top at Anfield? Can Klopp's energy prevail once more or will Van Gaal defy all the odds on Merseyside?