Attack coach Alan Dickens admits Saints were 'outmuscled' by Exeter Chiefs in the 43-28 defeat at Sandy Park.
The Chiefs scored seven tries as they claimed a bonus-point success in the Anglo-Welsh Cup opener.
Saints did grab a try bonus point of their own thanks to two efforts from Juan Pablo Estelles and one apiece from George Furbank and Rory Hutchinson.
But they were blighted by injuries, with James Craig, Christian Day and debutant Furbank all forced off early on.
And Saints were pushed around up front as Exeter made the most of the away side's disruption in a dominant home display.
"It's really disappointing, but this is a tough place to come," Dickens said.
"If you look back at it, we probably came unstuck early doors. We lost three players to injury and we had to make some adjustments.
"I still felt we were in it, but the last five or 10 minutes of the first half, Exeter were clinical. They scored two tries before half-time and they were clinical again after half-time.
"In terms of the positives, we fronted up, scored two good tries at the end and got the bonus point.
"Once we'd got the try bonus point, we wanted to push to get within seven and they might have got a bit twitchy if we'd scored again.
"But we got outmuscled up front today. That gave them good field position and they're a big pack who are hard to stop when they get on the front foot.
"They put our set piece under pressure and it's a hard game to play when you're struggling at the set piece."