The Spaniard overcame Fabio Fognini in the last 16 yesterday as he brushed the Italian aside 6-3 6-1.
Nadal goes into the match full of confidence with a 14-match winning streak behind him that includes a win over Dimitrov.
The Bulgarian came up against Nadal in the China Open semi-finals just six days ago and lost in straight sets.
Victory for Nadal today would take him to 870 career wins – tying Andre Agassi for sixth place on the Open Era career wins list.
Play is due to start at around 8am and you can follow live updates of the match below.
Rafael Nadal vs Grigor Dimitrov: LIVE Shanghai Masters updates
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*Nadal 0-1 Dimitrov
Dimitrov races two a 30-0 lead before Nadal gets his first point on the board.
The Bulgarian then sees out the game with a powerful serve to settle his nerves.
07:45: Both players will be due on court any minute now following Marin Cilic’s 6-3 6-4 win over Albert Ramos.