Remember when Manchester City walked the ball through Chelsea's flimsy defensive line almost at will? When they scored three times inside the first 34 minutes at Stamford Bridge and it could have been more.
That was on January 3, just two months ago, but back when it seemed any opponent could capitalise on the defensive insecurities of Frank Lampard's ailing side.
What a transformation in the two months that have passed. Since Thomas Tuchel replaced the sacked Lampard in late January, Chelsea have looked solid as a rock.
The German has overseen 10 matches and recorded seven wins, three draws and zero defeats.