Emery is currently the manager who can do no wrong, and it was his game-changing substitutions that turned this encounter on its head to confirm that Villa simply must be in the Premier League title conversation.
The Spaniard saw his side struggling to lay a glove on Chelsea, who were 1-0 ahead and comfortable, so acted decisively to set the platform for a superb victory.
He did not even wait until the hour before making the three substitutions that shifted the emphasis entirely in Villa’s direction.
Watkins, in particular, was transformative, as his pace and direct running suddenly caused havoc in a Chelsea defence that had been in cruise control.
He was razor-sharp, albeit with a sprinkling of good fortune, to pounce for Villa’s equaliser, then showed his power in the air to send an unstoppable header past the previously defiant Sanchez.
It came at the end of a spell of fierce Villa pressure as Chelsea wilted and Emery’s side grew in stature.
Villa remain hard on the heels of pace-setters Arsenal and Manchester City, with a visit to Emirates Stadium to come in three days’ time.
They will travel to north London with growing belief they can continue to shake up the established order at the top of the Premier League.
