At 15-30 Djokovic was called for a time violation for taking more time than allowed in between points. After slamming a forehand volley winner, the Serbian had words with the chair umpire then was booed by the French crowd.
Two holds of serve led to a decisive first set tiebreaker.
Federer, who had not lost a set this year in Paris, raced to a 4-2 lead after hitting an inside out down the line forehand winner. A Djokovic crosscourt forehand winner, followed by two Federer forehand errors put the Serbian ahead 5-4 in the tiebreaker.
However three groundstroke errors in a row from Djokovic would end the set in the Swiss’ favor after 70 minutes of play.
Federer would continue to cruise and take the second set before the newly slimmed down Djokovic thanks to a new diet would jump ahead 3-0 in set three.
Taking the ball earlier, Djokovic closed out the third set 6-3 as the threat of darkness began to loom over the center court.
In the final set, Djokovic went ahead 5-4 after breaking serve following a Federer framed forehand. However the Swiss would break back immediately in the following game to pull even at 5 all after connecting with an inside out forehand down the line winner.
As in the first set, a final hold of serve from both players resulted in a tiebreaker.
A Federer forehand dropshot winner followed by a crosscourt forehand winner put the Swiss ahead 2-0 in the tiebreaker.
Djokovic would pull even at 2 all before a Federer ace down the tee would put the Swiss far ahead once again at 5-3.
Djokovic netted a forehand return to set up triple match point for Federer at 6-3.
Federer netted a slice backhand to lose his first match point before Djokovic slammed an ace out wide to draw to 6-5.
But with darkness looming over the court, a final Federer ace down the tee would finish the match as the French crowd burst into
chants of “Roger, Roger.” Djokovic had not lost a match since losing to Federer in November.
In the men’s final Sunday, Federer takes on his old rival; the world number one Rafael Nadal of Spain who is 44-1 at the French Open.