Durban-based Coastal Sharks turned in a superb defensive performance to end Queensland's Super 15 title defence with a comprehensive 30-17 win on Saturday.
The Sharks repelled everything the Reds through at them to score three tries to two and set up a semi-final against the Stormers in Cape Town next Saturday.
After racing to a 17-0 lead in the first 20 minutes, the Sharks then held on for a comfortable win despite having only 31 per cent of the possession.
The Sharks defence was outstanding, with their forward pack dominant and their backline able to keep the Reds' dangerous back three under control.
Sharks captain Keegan Daniel later acknowledged that his side's defensive effort had proved the difference.
"That's what wins games and the boys put their bodies on the line," he said.
"It was very physical and hats off to both sides, there were some big hits in that game.
"I think the boys will be looking forward to the Stormers challenge -- we lost heavily there last time but this is finals football and if you win by one point, you win by one point."
The Reds' cause wasn't helped when they lost flyhalf Ben Lucas to injury after 20 minutes.
But the defending champions were their own worst enemies in the first half as they missed a host of tackles and made 13 handling errors, most in attacking positions.
Reds captain Will Genia said: "We were inside their 22 at the start of the game but we released pressure by knocking balls on at the back of the ruck."
The Sharks had silenced the home crowd early on with some brilliant attacking play, first weathering an early Queensland storm then hitting back in style.
French flyhalf Frederic Michalak kicked a penalty in the 10th minute, before winger JP Pietersen scored a simple try out wide after the Reds ran out of defenders in the backline.
Queensland then suffered a huge setback when Lucas, who was playing in place of the suspended Quade Cooper, injured his ankle and had to be replaced.
Will Genia moved to flyhalf with Nick Frisby coming on as scrumhalf and the Sharks took full advantage when centre Paul Jordaan scored a brilliant try following some superb lead-up work from Pietersen and Ryan Kankowksi.
Mike Harris got the home side on the board with a penalty, only for Michalak to restore the 17 point advantage with a smartly taken drop goal.
However, Genia began to find his feet at flyhalf and got the Reds back in the match with five minutes to go in the half when he scythed through the Sharks defence, passed out wide to No.8 Scott Higginbotham then took a return pass to score beside the posts.
Genia turned from hero to villain soon after halftime when his flat cut-out pass was intercepted by Sharks scrumhalf Charl McLeod, who raced 70 metres to score under the posts.
The Reds dominated possession in the second half and seemed to get their reward when flanker Liam Gill barged over, only for the television match official to rule no try despite replays showing otherwise.
"I thought we scored a try off Gill's pick and go, but I don't understand how it was wasn't conclusive," Genia said.
"I felt if we got that try we were back in the game -- it's very disappointing to finish on a sad note like that."
The decision seemed to take the sting out of the home side and the Sharks held on for a well deserved win despite a late Radike Samo try.