Or lack there of. The thing with Messi and Italian/Madrid defending is that Messi has too little room to glide or even try to fool. By making a human castle around him you make his moves very very limited. And I noted after watching many scenes again that Mou made sure that Varane or basically any other defender was never without support when he was around messi. so messi would not even have space to start to bomb forward the way he did with 7 defenders running after him with a fraction of second delay in madrid defense, made them basically unable to stop him ( but as expected he was all alone when it was time to make him an out let).
So whenever Messi was approaching Varane he was more than usually already drawn enough defenders to mark him to limit his choice of action and take away the time for him to fool the new defender he was approaching. In rare occasions that he was alone for Varane he did not have much chance because of having zilch support thanks to our midfield so even if he dribbled past him he would have lost the ball any way.
The thing is, Varane or any other top defender can not contain Messi
alone because finally his mind will get the better of yours you can not not fall for his technic because it is too varied for one person's skill set. As he comes nearer to your goal while your stress level builds up that reduces you focus, Messi will take advantage of every wrong breath you make, he would make an unpredictable pass, shot, sudden change of direction or simply controls the ball the way that is out of the defender's league.
Containing Messi as Mou found out last year is not a one man job. He used to put Pepe at it to have more fluidity with other players at ease, it didnt work because Pepe is brute force not a very intelligent defender and even if he was he would accumulate too many fouls to be worth it. So Mou changed direction with care, your guys are putting in HUGE work rate and pressing and compactness when the ball gets past their half line. that factor along with OUR immobility and lack of movement/pressing/work rate makes it much much easier to isolate a key player like leo messi. otherwise, with your defenders getting drawn to messi in groups of four or more, Messi would have basically made oceans of space for his teamates to cause damage that unfortunately was never taken advantage of. thus our players instead of having the plus of messi magnifying defenders and producing space, made madrid defense look better than it was (not that it was not good) by standing and watching while having iniesta trying some lone dribbling with no result.
take a look:
if Messi had a few feet more space behind him and had the two wingers' support, Varane or Ramos had near %0 of stopping him however intelligent the may have been. in such situations when messi decides to make a move either the defense is shut out nearly completely as he has done on too many occasions or ends in a foul that gives away a freekick that again with Messi's rapid improvement in that area, it would be a close goal enconter if not a direct goal.