#1 Jose Mourinho's tactical astuteness

Several times in the past, Jose Mourinho has proven that his shrewd tactics can win him games even when the odds are stacked up against his team. The Special One's ability to take match-winning decisions has enabled him to win games by making comebacks.
The FA Cup semi-final against Tottenham proves to be a relevant example of Jose's tactical astuteness. After going a goal down, the Portuguese gaffer inserted Herrera in the space that was being exploited by Dele Alli, a decision that neutralised Tottenham's attack. United clawed back in the game to emerge as 2-1 victors at the end of 90 minutes.
Mourinho's ability to make changes during games is something that Antonio Conte does not possess. Evidently, in a league game against Manchester City at the Etihad, the Italian didn't alter his tactics even after going a goal down, eventually losing the game 1-0.
His habit of shying away from making changes might as well affect Chelsea's last-gasp chance of winning silverware this season.