Western Province's recent resurgence continued when they claimed a 29-14 victory over the Blue Bulls at Newlands on Friday.
The result was sweet revenge for the hosts, who suffered a humiliating defeat to the Bulls in their corresponding fixture in Pretoria in Round Three.
Western Province's attacking enterprise and domination of territory and possession, especially in the first half, laid the groundwork to their victory and they outscored their visitors by three tries to one.
The Bulls often shone individually but seldom showed enough control when it mattered most and they committed basic errors which undermined their efforts.
WP made a superb start and were leading 5-0 after two minutes when Dillyn Leyds crossed for the game's opening try after running onto a pass from Johnny Kotze, who tore the Bulls' defensive line to shreds with a superb break in the build-up.
Robert du Preez added the extras and WP soon scored their second try when Huw Jones barged over from close quarters after shrugging off a tackle from Jamba Ulengo.
The visitors replied with two penalties from Louis Fouché, before Robert du Preez added one of his own to give the WP a 15-6 lead on the half-hour mark.
Fouché succeeded with another three-pointer from the kicking tee which meant the Bulls were still in the game at the interval.
Du Preez made it 18-9 five minutes after the restart when he added another penalty and for the next 15 minutes it was a war of attrition as both sides battled to gain the ascendancy.
WP drew further ahead with two Du Preez penalties and by the 65th minute they had the game in the bag with the score at 24-9.
There was some late drama when Travis Ismaiel got over for the Bulls' only try when he dived onto a perfectly-weighted grubber kick from Warrick Gelant behind the home side's tryline in 74th minute.
WP didn't panic, though, and still had time to score their final try three minutes before the end. Jano Vermaak was the man who put the final nail in his former side's coffin when he dived over after selling Ismaiel a dummy on the edge of the visitors' 22.
For Western Province:
Tries: Leyds, Jones, Vermaak
Con: Du Preez
Pens: Du Preez 4
For Blue Bulls:
Pens: Fouché 3
Western Province: 15 Cheslin Kolbe, 14 Dillyn Leyds, 13 Johnny Kotze, 12 Huw Jones, 11 Seabelo Senatla, 10 Robert du Preez, 9 Nic Groom (c), 8 Sikhumbuzo Notshe, 7 Rynhardt Elstadt, 6 Chris Cloete, 5 Ruan Botha, 4 Jean Kleyn, 3 Wilco Louw, 2 Bongi Mbonambi, 1 Steven Kitshoff.
Replacements: 16 Scarra Ntubeni, 17 Oli Kebble, 18 Chris van Zyl, 19 Nizaam Carr, 20 Jano Vermaak, 21 Demetri Catrakilis, 22 Kobus van Wyk
Blue Bulls: 15 Warrick Gelant, 14 Travis Ismaiel, 13 Dries Swanepoel, 12 Burger Odendaal, 11 Jamba Ulengo, 10 Louis Fouché, 9 Francois Hougaard, 8 Lappies Labuschagne (c), 7 Roelof Smit, 6 Deon Stegmann, 5 Marvin Orie, 4 Jacques du Plessis, 3 Marcel van der Merwe, 2 Bandise Maku, 1 Pierre Schoeman.
Replacements: 16 Jaco Visagie, 17 Werner Kruger, 18 RG Snyman, 19 Arno Botha, 20 Ivan van Zyl, 21 Tian Schoeman, 22 Jan Serfontein.
Referee: Rasta Rasivhenge