Sale boss Steve Diamond claimed Saints’ international stars looked ‘knackered’ after saluting his side’s victory at the AJ Bell Stadium on Saturday.
The Sharks secured a 19-6 success to end Northampton’s 11-match Aviva Premiership winning streak.
Tries from Mark Cueto, Marc Jones and Tom Brady before half-time gave Saints too steep a mountain to climb.
That was despite the fact they had their six Six Nations players back in the starting line-up as boss Jim Mallinder opted to throw them straight into the side.
And Diamond felt his men, who had three weeks off in the build-up to the game, were fitter than a Saints team that had lost to Exeter in the LV= Cup final just six days earlier.
“We’ve had a rest, they haven’t,” said the Sale boss. “We had two weeks off and they’ve played right through.
“Their internationals are obviously knackered, but they chose to pick them, it’s their choice. That probably shone through a bit.
“We looked the fitter team overall, certainly in the contact area we were brutal.”
Saints and Sale meet again at the AJ Bell Stadium on April 3 as they battle it out for a place in the Amlin Challenge Cup semi-finals.
And Diamond will take nothing for granted, despite his side’s victory on Saturday.
“They’re a top side,” he said. “We’ve had a good day but we play them in a fortnight’s time and it could be a different kettle of fish.”