There could be many reasons behind Chelsea's poor form this season and lack of mental toughness is certainly among them.
Ex-Spurs midfielder Jamie O'Hara said on ESPN FC: "I'll tell you what this Chelsea team is, soft! That's what they are, SOFT! They have gone soft as a football club!"
"I used to play against Chelsea when it was Michael Ballack, Frank Lampard, Didier Drogba, Michael Essien, Ashley Cole, John Terry. I rocked up thinking... oh here we go, we're playing against a brick wall today. Now? Get into them, they'll fold!
"What about Noni Madueke, Raheem Sterling, Moises Caicedo, Conor Gallagher, Enzo Fernandez? I mean, any danger of anyone else stepping up to the plate if Cole Palmer has an off-night?"
Chelsea conceded in the 38th minute against Boro and failed to pick themselves up and come back against a Championship side. Unfortunately, lack of urgency and desire to win is something we've seen too often from the Blues this season.