The black, green and gold were beaten 45-14 in the Champions Cup opener at cinch Stadium at Franklin's Gardens.
Courtnall Skosan and Fraser Dingwall scored for Saints but they were overpowered and outplayed by a rampant Racing team.
Wenceslas Lauret grabbed a hat-trick and Juan Imhoff doubled up as the French outfit cruised to victory.
And Boyd said: "We didn't get much going today.
"When they needed to they stepped it up a gear and we were certainly unable to live with them.
"There's certainly some lessons in there.
"I don't know whether we were tentative or nervous or just overpowered but they dominated that first quarter and we didn't adapt to the referee's interpretation. We paid the price.
"We weren't smart sometimes but I don't think we didn't try.
"We struggled to deal with the physicality and pace at times.
"There are lots of good lessons out there and if you aspire to improve, there are often some telling lessons.
"The boys are pretty down in the dressing room. They're pretty disappointed with the outcome and the performance.
"We've got to look at whether it was technical or tactical, but at the end of the day it was well short of being good enough to stay in the game."