Jim Mallinder has revealed how Courtney Lawes was suffering with illness before starring in Saints' stunning 23-22 win against Stade Français on Friday night.
Lawes produced yet another gargantuan display as he helped to carry his team past the French giants and into next season's Champions Cup.
The England lock was named man of the match for the third game in a row as tries from Ben Foden and Ahsee Tuala, allied with 13 points from the boot of Harry Mallinder, saw Saints home.
And Mallinder says Lawes did it all despite being under the weather earlier in the day.
"He was terrific again," the Saints boss said.
"I think that's three successive man of the match performances. I may be wrong, but I keep seeing him going up there and collecting something.
"He's been magnificent for us.
"He was a little bit poorly on the afternoon of the game. He had shivers and when you're not 100 per cent but put in a performance like that, it's really impressive."
Lawes will now link up with the British & Irish Lions for their tour of New Zealand.
And Mallinder added: "He's fit and raring to go for the Lions now."