The Waratahs held off a fast-finishing Force to ruin former coach Michael Foley's return to Sydney with a hard-fought 23-19 victory at Allianz Stadium.
Referee Steve Walsh's whistle was a constant presence in the first half as Brendan McKibbin kicked five penalty goals to Sias Ebersohn's three to give the hosts a 15-9 lead at the break.
McKibbin slotted another penalty goal immediately at the resumption before Adam Ashley-Cooper scored the first try of the contest in his 100th Super Rugby match to make it 23-9 to the hosts. But the plucky Force hit back with a converted try from full-back Alfie Mafi and cut the deficit to just four points on the hour via Ebersohn's fourth penalty goal.
Both sides had their chances in the closing stages but the Force finished the stronger of the two sides and were deep in attack after the final siren before prop Benn Robinson - also playing his 100th game - made a crucial steal.
McKibbin, who kicked six goals from eight attempts, kicked the ball into the stands to secure back-to-back victories for the first time this season. The win lifts the Waratahs to within a point of the top six while the Force picked up a bonus point for their efforts to move one point clear of the Rebels at the bottom of the Australian Conference.
Israel Folau had another strong outing for the hosts while fellow off-season recruit Michael Hooper had his best game in Waratahs colours in an outstanding individual performance. Force lock Hugh McMeniman was devastating in the tight all afternoon while number eight Richard Brown and Mafi continued their strong starts to the season.
Ebersohn and McKibbin traded two penalty goals apiece in the opening 20 minutes before Force prop Salesi Ma'afu was yellow-carded for a high shot on Tatafu Polota-Nau. McKibbin kicked two more penalties with Ma'afu in the bin as the Waratahs started to dominate.
The host followed Michael Cheika's instructions to fling the ball wide and came close to scoring their opening try on the half-hour. Folau made the initial break to put the hosts on the attack but Ashley-Cooper could not hold Drew Mitchell's final pass as the try line beckoned.
They chanced their arm from first phase again moments later as the dangerous Folau unleashed Peter Betham down the right wing. Betham kicked ahead for himself and the Force were penalised for sealing off, with McKibbin nailing his fifth penalty from out wide.
Folau beat three defenders after the resumption to spark a Tahs attack, with Bernard Foley finding Ashley-Cooper in the next phase to cross over. Mafi's response was equally impressive, the former Waratah carrying Mitchell and McKibbin over the tryline to set up a grandstand finish, but the Force could not find the extra score they required.