A length-of-the-field Luke Morahan try ruined Rebels captain Scott Higginbotham's farewell as the Force pulled off an upset over the third-ranked Australian conference side away.
Higginbotham, who will join Japanese club NEC Green Rockets after this year's World Cup, was one of his side's best.
But the Wallabies back-rower was denied a winning swansong by two superb individual acts from Morahan.
The Force winger first calmly collected a chip kick from Higginbotham, who was in a great position to grab the opening try after a clearing kick fell his way in the second half.
Then 18 minutes later when the Rebels were threatening, Morahan dashed away straight down the middle of the field to score after a Marcel Brache intercept to give his side a 13-6 lead.
Telusa Veainu came off the bench to cross in the corner in the 72nd minute to make things interesting in an overall drab match between both sides out of the play-off reckoning.
However, Mike Harris failed to convert to level the scores.
Harris also put a late drop goal attempt wide.
The Force led 6-3 at half-time after the television match official (TMO) had a big say in proceedings.
Rebels winger Cam Crawford looked to have scored the game's opening try in the 31st minute, following up a brilliant run with a show of strength on the line.
It was disallowed by the TMO, who penalised Tom English for obstruction.
The Force then celebrated prop Chris Heiberg's bulldozing effort, only for replays to confirm Sam Jeffries had slipped an arm under the ball. – AFP
Original source: Western Force scrape past Rebels