Waratahs skipper Dave Dennis was left disappointed after a late charge from the Bulls denied his team their first win in Pretoria in 11 years.
After outscoring the Bulls by three tries to two, the Waratahs led 19-15 going into the final 15 minutes but a try from Bulls' fly-half Morne Steyn - added to his 20 points with the boot - stole the win for the home side and denied the visitors a well-deserved losing bonus point.
"We came here to win obviously. In the second half we were right back in it and took the lead only to lose in the end," said Dennis.
"Against the Bulls you've got to be physical, defence was a key part of the game and poor discipline hurt us in the first half.
"It was hard to come back."
Michael Cheika's men now travel to Port Elizabeth to face this year's Super Rugby newcomers the Kings, with Dennis describing the game as another big challenge for the team.
"We're going to have to work hard, they're a quality team and they've knocked off a few teams already this year," he said.
"They'll be a big crowd down there in Port Elizabeth and it'll be a new experience for the boys. We'll have to train hard this week and try and get a result."