Wilson is the only player among the four semi-finalists who is yet to win the Masters, although he finished as runner-up to Allen in 2018.
The 33-year-old said his quarter-final win was “one of the best” of his career after a strange build-up.
He told BBC Four: “I could make up an extravagant story but literally I fell asleep in bed.
“You know when you’re in a hotel and they tuck the quilt into the mattress? My foot has landed in an awkward position for eight hours. I woke up and I couldn’t move.
“I fell asleep in bed and sprained my ankle – who does that?”
Despite those pre-match issues, Wilson began in clinical form against Brecel, the man he succeeded as world champion, seizing on the opportunities presented to him by his opponent to forge ahead.
Wilson made five half-centuries during an engaging last-eight tie in which Brecel was never more than two frames behind.
The Belgian, helped by breaks of 96, 84 and 83, reduced his deficit to one frame on four separate occasions.
After missing a chance to wrap up victory in a lengthy ninth frame, Wilson took a gripping 10th – which lasted more than 40 minutes – on the pink to confirm his place in the last four.
