The Sharks booked a home Currie Cup Semi-final next week when they comfortably beat the Blue Bulls 20-3 at a wet Kings Park Stadium in Durban.
Three first-half penalties from the young flyhalf put the hosts 9-0 up at the break, before two more penalties and a late Lwazi Mvovo try ensured that John Plumtree's men will host next week's decider.
The Sharks fully deserved their win, almost entirely dominating against the side from Pretoria, who had to play with 14 men for a period in the first half after a professional foul by Morne Mellett.
The two sides seemed reluctant to hold on to the ball during the early exchanges, while the hosts fluffed their first attempt at goal when a fifth-minute Lambie penalty from close to the halfway line dropped well short.
The kicking trend continued for most of the opening quarter, before the Sharks finally went ahead with a 22nd minute penalty from Lambie after Jano Vermaak was penalised for being off-side.
The Bulls were reduced to 14 men on the half-hour mark when prop Mellett was yellow carded for a cynical trip of Lambie after he kicked forward and looked to collect five metres short of the tryline.
Lambie slotted over the penalty and added another moments later when Francois Venter failed to release in a tackle after a fine initial chase by winger Mvovo.
It was a deserved lead for the Sharks at the break and after the restart Lambie extended the advantage when flanker Jacques Potgieter failed to roll away.
There was finally an attacking chance for the visitors 10 minutes into the second half, but they were thwarted on the line by some solid home defence -- a free-kick turning into a penalty to add insult to injury for the Bulls after some back chatting to referee Mark Lawrence.
The Bulls seemed to suddenly find momentum going forward, only for JJ Engelbrecht to knock on when they found an attacking gear.
Winger Bjorn Basson then missed a pass as he charged forward, before Pine Pienaar's men eventually won a penalty within kickable range after Steven Sykes took too long to roll away from a ruck.
Morne Steyn converted the penalty but the Sharks hit straight back, again through Lambie, to retain their 12-point lead.
With six minutes to go, Mvovo capped a good team effort by diving over on the left to clinch the win.
Final Score Natal Sharks 20 (9) Blue Bulls 3 (0)
Tries : L. Mvovo
Penalties : P Lambie 5
Penalty : M Steyn
Referee: Mark Lawrence
Assistants: Jason Jaftha, Christie du Preez
Television Match Official: Shaun Veldsman
Sharks - 15 Louis Ludik, 14 JP Pietersen, 13 Paul Jordaan, 12 Tim Whitehead, 11 Lwazi Mvovo, 10 Pat Lambie, 9 Cobus Reinach, 8 Keegan Daniel (capt), 7 Jean Deysel, 6 Marcell Coetzee, 5 Anton Bresler, 4 Jandr e Marais, 3 Jannie du Plessis, 2 Kyle Cooper, 1 Dale Chadwick.
Replacements: 16 Craig Burden, 17 Tendai Mtawarira, 18 Wiehahn Herbst, 19 Steven Sykes/Peet Marais, 20 Willem Alberts, 21 Charl McLeod, 22 Meyer Bosman.
Blue Bulls - 15 Zane Kirchner, 14 Akona Ndungane, 13 JJ Engelbrecht, 12 Francois Venter, 11 Bjorn Basson, 10 Morne Steyn, 9 Jano Vermaak, 8 Arno Botha, 7 Jacques Potgieter, 6 Dewald Potgieter (capt), 5 Juandr e Kruger, 4 Flip van der Merwe, 3 Werner Kruger, 2 Willie Wepener, 1 Morn e Mellett.
Replacements: 16 Chiliboy Ralepelle, 17 Frik Kirsten, 18 Wilhelm Steenkamp, 19 CJ Stander, 20 Francois Hougaard, 21 Louis Fouche, 22 Dean Greyling.