Berdych, the only member of the world's top 10 without a title this year, lost an opening-set tie-break against the Frenchman but recovered to win 6-7(5) 6-2 7-5 in Bangkok.
The Czech served 20 aces in the near three-hour contest and will need to serve well again on Sunday against Canadian powerhouse Milos Raonic who beat defending champion Richard Gasquet 3-6 7-5 6-4.
Having worked his way to the brink of victory against Simon, who had won their last three encounters, Berdych stumbled when serving for the match, going 0-40 down.
He got the benefit of a tight line call at 30-40 and went on to complete victory in a touch under three hours.
Raonic is bidding for his second title this year and a strong end to the season could put him in the frame for a place in the ATP World Tour finals. World number six Berdych is already well-placed to qualify.
- Sports & Recreation
- Milos Raonic
- Richard Gasquet