So far, pre-season friendlies for Newcastle United have highlighted a glaring weakness in defence - which, let's be fair, has been the biggest issue at the club for a number of years now. Ten goals conceded in six games, all against opposition well below Premier League standard, is almost certainly not the start that Messrs McClaren and Cathro expected, even without club captain Fabricio Coloccini. Help is on its way though as the club's brain trust of Steve McClaren, Graham Carr and Lee Charnley have finally forced their third deal of the summer over the line. With Chancel Mbemba following Aleksander Mitrovic from Belgian side Anderlecht, the club have brought in another highly-rated young talent to solidify the middle of the defence. At just 20 years of age (probably) the Congolese international is not projected to be the finished article by any means. With Champions League experience and a Belgian title already in the bag, it is expected that he could be a key part of McClaren's plans for many years, especially with a number of the club's centre-backs out of contract next summer. Defensive solidity is not a trait commonly associated with Newcastle United. There have, however, been some centre-backs that have played for the club that Mbemba would be wise to look up on YouTube for their best moments if really he wants to push his game forward. Here's the 10 NUFC centre-backs Mbemba should be looking to emulate...