In Saturday's semifinals, del Potro will play doubles specialist Edouard Roger-Vasselin of France, who beat Daniel Brands of Germany 6-3, 4-6, 6-3.
John Tomic, who also coaches Bernard, is barred from tournaments by the ATP and International Tennis Federation.
Monfils had 16 aces to set up a meeting with sixth-seeded Florian Mayer, who defeated another German, Andreas Beck, 6-4, 3-6, 6-1.
Frenchmen Michael Llodra and Paul-Henri Mathieu have joined seven players who pulled out on Wednesday.
Mahesh Bhupathi-Julian Knowle beat Argentine-Spanish duo Leonardo Mayer and Albert Ramos 6-2, 6-7(5), 6-4, 6-2 in two hours and 37 minutes in the first round clash.
Nadal will play a Saturday semi-final against Canadian fifth seed Milos Raonic, who beat Ernests Gulbis 6-2, 7-6 (8/6) and followed up by winning a hard-fought battle with Spanish veteran Tommy Robredo 6-7 (5/7), 6-3, 7-6 (7/2) in almost two and a half hours.
Djokovic is bidding to become the first player in the Open Era to win three consecutive Australian Opens and was in a different league to Mathieu, running through to his 15th straight match win in Melbourne.
Third seed Roger Federer beat Spain's Albert Ramos 6-1, 6-1, 6-1 on Monday to reach the Wimbledon second round.
This, then, is who John Isner is for now: The Marathon Man of Tennis, the guy who plays and plays and plays, for hours on end, until the last set seems interminable.
Veteran Czech Radek Stepanek on Tuesday ended the Madrid Masters run of Australian Bernard Tomic in the first round, with the Queensland youngster exiting 6-2, 7-5.
Top seed Juan Martin del Potro and number two seed Richard Gasquet set up a duel for the Estoril Open title as the pair advanced to the final on Saturday.
Jurgen Melzer of Austria and Paul-Henri Mathieu of France both won in straight sets to reach the second round of the Monte Carlo Masters on Monday.
Paul-Henri Mathieu fought back from a set down on Monday to upset fourth-seeded Feliciano Lopez 4-6, 7-6 (5), 6-4 in the opening round of the ABN Amro World Tennis Tournament.
Sweden's Robin Soderling reached the third round of the French Open on Thursday with a 6-3, 6-4, 6-4 win over Spanish qualifier Albert Ramos.