#4 Chelsea have committed a handful of individual errors

Believe it or not, the individual errors by certain players have played a major role in Chelsea's dismal run of form throughout the season. The Blues have committed unexpected mistakes in crucial games, paying a heavy price eventually.
In the Champions League, individual errors from Thibaut Courtois led to Barcelona qualifying for the quarter-finals. Even in their last two league games against Newcastle and Huddersfield that they direly needed to win in order to secure a UCL qualification, the Blues were found giving away too many free-kicks around the box while their individual mistakes made them lose points in both games.
Against Manchester United, if they repeat the same mistakes, expect Antonio Conte and co to lose the FA Cup final for the second time in a row.