The Wales international had been stuck on 99 for three outings.
But he returned to the net on Saturday to reach a notable landmark on the biggest of occasions for Real.
Santiago Solari’s side made the short trip to Wanda Metropolitano aware of the importance being placed on a derby date.
Bale was only named among the substitutes as Real went in search of a priceless win that would see them close the gap on Atletico and table-topping Barca.
He was introduced in the 57th minute and needed just 17 to get his name on the scoresheet.
His big moment arrived when freed into space on the left of the box, with one touch required to set himself before looking up and drilling low across Jan Oblak.
As the net rippled, Bale was able to wheel away and celebrate becoming a Madrid centurion.
Bale’s 100 goals for Madrid have come in 217 appearances.
He has endured his fair share of injury struggles while in the Spanish capital, but has delivered a healthy return of end product.
Twelve efforts have been recorded across all competitions this season, with six of those coming in La Liga.
He will be hoping that there are many more to come as Real continue to chase down major honours.
The 20-goal mark has been reached in two of his five seasons to date, with it still possible that he can add a third entry to that list this term.
Much has been expected of him since Cristiano Ronaldo departed for Juventus last summer, and more contributions such as that made in a derby duel with Atletico will help him to win over his doubters.