Jose Mourinho is often known as one of the best matchday tacticians in the game and would often have a set plan for every game.
No more so than when he was Manchester United boss and they would come up against their rivals and his former club Chelsea.
There is no doubt that the Blues' biggest threat is on the left wing and with Eden Hazard, with the Belgian having the most productive season in a Chelsea shirt.
With 16 Premier League goals so far and 13 assists, the 28-year-old is obviously the man that Ole Gunnar Solskjaer will be aiming to stop on Sunday.
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During his tenure at United, Mourinho had one specific tactic that often worked again Hazard, especially when the Blues were making the trip to Old Trafford.
That was to man-mark Hazard out of the match using a key player that has just recovered from injury and could well be in the starting XI at the weekend.
Mourinho settled on Ander Herrera to be the man to track Hazard's every move and at Old Trafford, the past two seasons, it really worked to a good effect.
"I would think so yeah," Solskjaer said about Herrera's return for the weekend. "There’s three games left and Ander's been training, enthusiastic and will probably be involved on Sunday, can't guarantee but he's trained the last two days. He’s been injured."
Solskjaer has created a new style at United, although performances of late have taken a nose-dive with a heavy defeat to Everton and then losing to Manchester City at on Wednesday night.
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The United boss will be looking to get his team back to winning ways and one idea he might have is to learn from his predecessor and use Herrera to negate Hazard.
With Herrera in the side under Solskjaer, United have won eight out of nine matches, drawing the other, and they have massively missed him. They have lost four games out of nine when he has not started, winning just four as well.
So for Hazard and Chelsea the fact that Herrera is back in the squad and potentially ready to take on the challenge of the Belgian could be something of a worry.
However, Hazard has been in blistering form this season that he would feel he could have the upper hand over the Spaniard.
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