Leicester Tigers boss Geordan Murphy admits Saints performed 'at a higher level' than his team at Franklin's Gardens on Saturday afternoon.
Murphy saw his side slump to a 36-13 defeat as Saints ran riot, scoring five tries in a comprehensive home success.
Leicester had led on a couple of occasions early in the game, but they were eventually blown away.
Matt Proctor scored twice for Saints, with Api Ratuniyarawa, Tom Collins and Fraser Dingwall helping to deliver a bonus-point success.
It meant Saints went back to the top of the Gallagher Premiership, while Tigers are still languishing second bottom, only above Saracens due to the Allianz Park club's 35-point deduction for salary cap breaches.
And Murphy said: "We just didn't get our game going at any part of the day.
"I thought at 10-10 we had some opportunities in Saints territory and they defended stoically.
"We didn't attack as we'd have liked and we wasted some opportunities to build up some pressure.
"Fair play to Saints, when they were given chances they scored and everything stuck for them.
"We had an attacking lineout late in the first half at 17-10 down but they went up the other end of the field and scored.
"I felt we could claw it back, but it was a huge moment and it really took the wind out of our sails.
"We've got to learn the lessons and look at ourselves.
"Saints were a better team than us, they performed at a higher level and were the better team. You can't hide from that.
"We need to look at our training schedule because we were a bit flat, their physicality was a lot better than ours and they really stopped us on the gainline.
"They looked good, but credit to our boys for sticking at it.
"We started to chase and they just kept turning us.
"We found ourselves trying to play from deep and they capitalised with a couple of late tries.
"We're always concerned and the easy thing to do is to say 'it's only five games', but our form needs to be better.
"We knew it would be difficult without our internationals and we came through that, so this result is particularly disappointing.
"A lot of things need to function for us and we have to take our medicine."