Sale Sharks boss Steve Diamond says Saints were 'singing as if they'd just won the league' after Saturday's Anglo-Welsh Cup clash at the AJ Bell Stadium.
Nafi Tuitavake's try provided a dramatic late victory for the black, green and gold, who were 24-20 winners.
Earlier scores from Ken Pisi and Ben Nutley set Saints up but they went 20-17 down before battling back in the final play of the game.
It was a third win in four matches in all competitions for Northampton, but Diamond was not overly impressed.
“I’m not too despondent and fair play to Northampton, for them to rock up with their full-strength side, or £10million-worth, good luck to them," Diamond said.
“They were singing as if they’ve just won the league in the changing rooms there so good on them, we will just get ourselves ready for London Irish in the league.
“Northampton have obviously got their backsides into gear a little bit and fair play to them for playing the full 80 minutes, and scoring in the end.”