The black, green and gold failed to score a single point during a hugely disappointing second half as the Sharks showed their bite on home soil.
Tries from Rohan Janse van Rensburg and Akker van der Merwe got the job done for Steve Diamond's men.
And Saints were left to reflect on a display in which they never really fired, ensuring they dropped off the top of the Gallagher Premiership table before Christmas.
"We got sucked into an arm wrestle that we didn't want to have," Boyd said.
"To be fair to them, they forced us into spaces we didn't want to go into.
"It certainly wasn't the game we wanted to play and they were on the front foot and dictated it to us.
"Guys were spooked into poor execution and poor decisions under pressure - we've just got to get better at that.
"It was a very frustrating day at the breakdown and when you can't get any ruck speed it changes the picture quite a lot.
"We need to go back to some really key little parts of our game and make sure we get it right."
Saints have now lost three successive matches in all competitions following the two defeats to Leinster in the Champions Cup.
But when asked whether he was worried by recent events, Boyd said: "Not at all.
"You have to take the two Leinster games out because we didn't have a great performance at home, got well beaten and took half a team over there.
"We probably did a bit better (in Dublin) because we got three tries there rather than the one we got at home.
"One swallow doesn't make a summer either positively or negatively and we'll just go back to the drawing board.
"We saw a really impressive Gloucester performance (against Worcester) last night and we're going to have to play a lot better to get something at home next Saturday."