Coming off a bye in the last round the Chiefs made a slow start and found themselves trailing by seven points following a converted Tom Kingston try in the fifth minute.
Robbie Robinson replied five minutes later, running in a slick try which Aaron Cruden easily converted.
Brendan McKibbin and Cruden then traded penalties before the Chiefs grabbed the lead before halftime, Cruden kicking over from close range.
At halftime the Waratahs had twice as much possession and territory as the Chiefs but the scoreboard told the story of a side who can win even when they are far from top gear.
The second half started with a bang, charismatic loosehead prop Sona Taumalolo finding himself free out wide to touch down - making him the Chiefs leading try scorer this season.
Cruden converted creating a 10 point buffer, which was soon reduced to seven, when Ben Tameifuna conceded a scrum penalty which McKibben knocked over.
Cruden restored the 10-point buffer before Sam Cane grabbed an intercept setting up Liam Messam in the corner to put the score out of reach.
CHIEFS 30 (Liam Messam, Robbie Robinson, Arizona Taumalolo tries Aaron Cruden 3 cons 3 pens) bt NSW WARATAHS 13 (Tom Kingston try Brendan McKibbin con 2 pens)