The win ensured a quarterfinals berth in the competition for the side but the former Hurricanes coach wasn't happy.
"I apologise to everyone for that performance. It was a horrible game. I thought we were terrible," he said.
"Anyone with any respect for the game would be horrified by that performance from both sides. I don't need to say anything to the players, they're apologising to each other. I don't think we showed respect to the game or the opposition."
Boyd said the plan had been to secure five points to keep them alive in the competition but it seemed every time the players secured the ball they felt they had to score a try.
"All the fundamentals and basics go out of the game. I hate to think of the number of times during the week that we said it had to be built on a solid foundation of performance.
"The only positive for me is that we're going through a period of rest, rotation and regeneration. Dan Biggar, Alex Waller and Tom Wood were rotated out and those guys tend to be key around driving the ship and keep the standards high. With all those guys away at one time, it became a perfect storm," he said.
Gloucester also kept their hopes alive with a 29-6 bonus point win over Montpellier. Halfback Willi Heinz was among the try scorers while Jason Woodward's tap pass to wing Louis Rees-Zammit was crucial in his try.
Toulouse captain and former All Black Jerome Kaino got among the try-scoring action in his side's qualifying 21-7 win over Connacht.
Kaino said the win was a big boost ahead of their final pool game against Gloucester.
"It would have been good to get a bonus point but we didn't execute things as well as we would like and Connacht battled hard," he said.
Toulouse played out the game with 13 men but held on to win. Prop Charlie Faumuina turned in a man of the match performance for Toulouse.
Dave Rennie's Glasgow side saw their hopes ended when drawing 31-31 with Exeter.
In the Challenge Cup Wasps beat Agen 52-24. Former Hurricanes and Blues five-eighths Jimmy Gopperth, who played second five-eighths, scored two tries while inside him former All Blacks and Highlanders five-eighths Lima Sopoaga landed six conversions for Wasps.
Pat Lam's Bristol secured a home quarter final as a result of their 52-3 win over Brive.