The Ivorian found half a yard inside the area and swept the ball home confidently from Branislav Ivanovic's pinpoint low delivery which came at a timely part of the match for Mourinho's men who had earlier conceded to Marc Albrighton.
Mourinho said: "His goal is gold because we were losing, because it's the beginning of the second half and because it was a great motivation for the team.
"It's not just about the goal, it's about his spirit, his mobility, the fact he's the only striker we have at the moment and he has to play for the whole 90 minutes against difficult guys to play against. He was there for us."
The goal was Drogba's fourth in the league this season for the Blues.