The 23-year-old world number two lost his quarter-final tie 6-1 at Alexandra Palace on Friday.
Dott won the first two frames before Trump threatened a comeback by clinching the third.
However, the 35-year-old won the following four frames to register a comfortable victory.
"I have not really had any form for the last four to five months," Dott told BBC Sport. "I have been struggling and I am not cueing very well, but I am slowly getting there.
"Luckily for me, Judd did not show up today. You expect him to play well and sometimes when someone doesn't play well, it affects your game. I seemed to struggle too.
"It is unusual for Judd to play as bad as that, but I was happy for this match to be a tactical one."
Selby won the first four frames before his Welsh opponent reduced the deficit to 4-1, only to lose the following two to relinquish his hopes of advancing further in the competition.
Dott and Selby will take on each other for a place in the final.