But the 63-year-old stressed there were still some important lessons to learn as a rampant Racing side ran in five tries in an entertaining Pool A clash at cinch Stadium at Franklin's Gardens.

Flanker Wenceslas Lauret scored a hat-trick of tries, with Argentine wing Juan Imhoff crossing for two, while Maxime Machenaud kicked 20 points for the French team.

Fraser Dingwall and Courtnall Skosan bagged Saints’ tries, but Racing bossed the contest as they powered into a 23-0 lead midway through the first half.

“The guys are disappointed with the outcome and disappointed with the performance, so we’ve got to sort that out, whether it’s technical or whatever those reasons were,” Boyd said.

“But at the end of the day, it was well short of being good enough to put enough pressure on to stay in the game.”

“We didn’t get much going today. When they tried to step up a gear, we were unfortunately unable to live with them, so there’s certainly some lessons in there.”

Reflecting on Racing’s early onslaught, Boyd said: “I don’t know whether we were tentative, or nervous or just overpowered, but they certainly dominated that period of time. We didn’t adapt to the referee’s interpretation [of the breakdown] and paid the price.

“We weren’t smart sometimes, but I don’t think we didn’t try. I think we struggled to deal with their physicality and pace at times.

“If you aspire to improve then when you don’t get it right, there’s often some pretty telling lessons in there.”

Northampton, who visit Ulster Rugby in Round 2 on Friday, are now likely to be without their British and Irish Lions fly half Dan Biggar for a few weeks after he limped off injured early in the second half.

“He has carried that thigh [injury] for a couple of weeks now," Boyd revealed. "We thought it was good and he trained well last week, but he just overstretched a lunge very early on.

“He and Matt [Proctor] both struggled. There was a bit of a problem because we couldn’t finish the game with a full side. It was unfortunate, but sometime sit goes like that.”

Northampton Saints director of rugby Chris Boyd admitted his side were not good enough in their 45-14 opening round home defeat to Racing 92 in the Heineken Champions Cup on Friday.