Djokovic, who won in Paris in 2009 and is not only chasing a 40th ATP title but also the World No 1 spot, dropped the first set before storming back for a 6-7 (5/7), 6-1, 6-3 victory.
He now meets Wawrinka against whom he has already played some classic matches this season, notably their five-set epic in the US Open semi-finals where the Serb finally prevailed.
Wawrinka took another step towards booking his Eurostar ticket earlier when he comfortably defeated Spaniard Nicolas Almagro 6-3, 6-2.
Seventh-ranked Wawrinka will make the cut for the season’s grand finale in the English capital, should either Richard Gasquet or Milos Raonic lose their third round matches later in the day.
Ferrer showed little mercy against Simon and now faces a potential Last Eight tie against sixth seed Thomas Berdych or Raonic.
Roger makes ATP finals cut
Meanwhile, Roger Federer, who had earlier sealed his berth at the season-ending World Tour Finals, overcame Philipp Kohlschreiber 6-3, 6-4. This year will mark Federer’s 12th straight appearance at the World Tour Finals.