They could host their first final should they win their semifinal in two weeks' time
The Stormers saw off the challenge of a spirited Rebels side who they edged out 26-21 at Newlands to finish on top of the Super Rugby standings.
The victory was the Cape side's 14th of the season and means that they could host their first final should they win their semifinal in two weeks' time.
The Rebels had little to lose at the end of a long season and they played with plenty of heart in what was a Super Rugby swansong for veterans Stirling Mortlock, Mark Gerrard and Julian Huxley but came up just short.
The Stormers pinned the opposition back in their own half from the first whistle, and the territorial pressure yielded early points as the Rebels conceded two penalties in front of the poles that were duly slotted by Peter Grant.
With a six-point buffer in place the home side had a chance to show what they are capable of with the ball in hand, and they took the game to the Rebels by running from deep following a stolen line-out.
They gave the ball width, with lock Andries Bekker prominent in a few flowing attacks, and the Rebels' defence was eventually stretched, giving outside centre Juan de Jongh the opportunity to step his way over the tryline following a broken tackle on the 22.
The Rebels were intent on building phases and controlling possession but struggled to penetrate the Stormers' aggressive defensive system which showed good discipline to repel them without conceding points.
The home side's physicality backfired somewhat when Gio Aplon was knocked out by his teammate Rynhardt Elstadt, but the Springbok outside back somehow got up and carried on playing.
A high tackle from Elstadt gave the Rebels a prime attacking opportunity and they camped on the Stormers' tryline for some time but could not find a way through, and the home side were next to score with a late penalty from Grant sending them into half-time with a 16-0 lead.
The Rebels continued to carry the ball at the Stormers after the break, showing positive intent by repeatedly rejecting the opportunity to kick at goal.
Their control and patience was eventually rewarded when the ball was forced over the tryline amongst a pile of bodies following a powerful forward drive, and when scrumhalf Nick Phipps nipped over for their second try shortly afterwards the Melbourne side were right back in the contest at 16-14.
The Stormers had allowed the visitors right back into the game and needed to respond which they did immediately as De Jongh surged over for his second try.
Bryan Habana claimed the restart and got good support as they rolled into the 22 where Grant turned the ball on the inside for De Jongh who coasted through under the poles.
That try seemed to inject some confidence into the Stormers as they got on the front foot once more, but their progress was stunted by a few crucial handling errors and the Rebels took advantage.
The visitors hammered away at the Stormers defence and their hunger was satisfied when replacement Cooper Vuna was put over for a relatively soft try that brought his team right back in it at 23-21.
The home team's nerves were settled by a late Grant penalty which stretched their advantage to five points at 26-21 and managed to hold on for victory despite late pressure from the willing Rebels who deserved more than the solitary bonus point they earned.
Man of the match: Juan de Jongh did well to finish his two tries but the real hero for the Stormers was hooker-turned-No.8 Deon Fourie who made a number of important turnovers, ran well with the ball and even took a line-out ball.
For the Stormers:
Tries: De Jongh 2
Cons: Grant 2
Pens: Grant 4
For the Rebels:
Tries: Blake, Phipps, Vuna
Cons: Huxley 3
Stormers: 15 Joe Pietersen, 14 Gio Aplon, 13 Juan de Jongh, 12 Jean de Villiers (captain), 11 Bryan Habana, 10 Peter Grant, 9 Dewaldt Duvenage, 8 Deon Fourie, 7 Rynhardt Elstadt, 6 Siya Kolisi, 5 Andries Bekker, 4 De Kock Steenkamp, 3 Frans Malherbe, 2 Tiaan Liebenberg, 1 Steven Kitshoff.
Replacements: 16 Brok Harris, 17 Deon Carstens, 18 Quinn Roux, 19 Jebb Sinclair, 20 Louis Schrueder, 21 Burton Francis, 22 Gerhard van den Heever.
Melbourne Rebels: 15 Julian Huxley, 14 Mark Gerrard, 13 Mitch Inman, 12 Stirling Mortlock (captain), 11 Lachlan Mitchell, 10 James Hilgendorf, 9 Nick Phipps, 8 Gareth Delve, 7 Hugh Perrett, 6 Tim Davidson, 5 Hugh Pyle, 4 Cadeyrn Neville, 3 Jono Owen, 2 Ged Robinson, 1 Rodney Blake.
Replacements: 16 Luke Holmes, 17 Paul Alo-Emile, 18 Alister Campbell, 19 Ryan Hodson, 20 Nic Stirzaker, 21 Cooper Vuna, 22 Richard Kingi.
Referee: Lourens van der Merwe (South Africa)
Assistant referees: Mark Lawrence (South Africa), Christie du Preez (South Africa)
TMO: Shaun Veldsman (South Africa)