With no points scored in the second half, Crusaders number eight Cullen Grace grabbed a decisive brace of first-half tries and Richie Mo'unga gave a masterclass at flyhalf on a drizzly night at Orangetheory Stadium.
However, it was gut-busting defending after the interval to stifle a relentless Chiefs attack that ensured Scott Robertson's team extended their perfect record in home playoffs to 27 wins.
Bidding for a sixth championship trophy in as many years, the Crusaders will meet the winner of the Auckland Blues and ACT Brumbies who play the other semi-final at Eden Park on Saturday.
"It was a huge effort. I'm immensely proud of the boys," said Crusaders skipper Scott Barrett.
"You have to take your hats off to the Chiefs. They threw 120 percent at us and I'm sure there are going to be some sore bodies over the next few days."
The Chiefs needed everything to go right for them to upset the Crusaders but suffered a terrible opening quarter and blew three hot try chances.
Down 6-0 after two early Mo'unga penalties, the Chiefs saw the first try go begging when Pita Gus Sowakula failed to ground the ball in the 12th minute.
The Chiefs wasted the second chance on the cusp of halftime when Alex Nankivell flung a wide ball straight to Crusaders winger Leicester Fainga'anuku.
Fullback Josh Ioane later sent a pass sailing over Quinn Tupaea's head into the terraces as the unmarked centre streamed toward the right corner in the 54th minute.
The Chiefs battled to the finish but were constantly repelled by the wall of red-and-black jerseys as the Crusaders stayed firm in an attritional second half to set up another championship match in a week's time.