Up against a ruthless and commanding Bulls pack, and some outstanding play by centres Jan Serfontein and JJ Engelbrecht, the Kings were outclassed in front of a capacity crowd at the Nelson Mandela Bay Stadium.
It was a disappointing result for the home team, particularly after having done well towards the end of their overseas trip.
VIDEO: Kings v Bulls, highlights
The Bulls picked up an important five points and boosted themselves to the top of the South African conference.
"We weren't in the game at all," Watson said.
"The Bulls were in top form, very accurate and very clinical in everything they did.
"They took us out of the game and we never rocked up, so it was a disappointing evening for us."
Watson was reluctant to give any excuses for their performance, but did cite the travel factor and some inexperience as possible causes.
However, he emphasised that the Kings would have to lift themselves up from this performance.
"We have to bounce back from this," Watson said. "We know the nature of the competition and we have to bounce back. We have no option here.
"We know the Cheetahs will be very tough next week, but we have to pick ourselves up."
Meanwhile, Bulls captain Pierre Spies was delighted at picking up the five points in a match they knew would be a challenge.
"It was a great performance by our boys; very happy with the result," Spies said.
"We had a few injuries during the match and couldn't find our feet for a while, but the last five minutes we went into overdrive (to score two tries) and I am proud of the effort."
Spies said the Pretoria outfit had worked hard during the week leading up to the clash, with possession and control a priority.
"We tried to control the ball and possession and wanted to finish off that pressure by turning it into points as much as we can, and we did that well tonight."
Man-of-the-match Jan Serfontein was happy with his performance and is enjoying his time at the Bulls.
"The Bulls is a great place to be with great facilities and very happy with where I am, but Super Rugby is very tough and I am sure I will be a bit sore after this game," he said.