Luther Burrell felt tiredness took its toll on Edinburgh as Saints claimed their third successive pre-season win on Friday night.
Burrell and Co racked up a 24-6 win at Franklin’s Gardens thanks to two tries from Phil Dowson and one from Ken Pisi.
Edinburgh could only reply with two Greig Laidlaw penalties as their defiant defence was eventually broken down.
And Burrell believes Saints’ superior fitness told, a good sign with just two weeks to go until the Premiership opener, against Exeter at the Gardens.
“Edinburgh are a very well-drilled outfit and it took a long time to grind them down,” said the centre.
“Fortunately for us, their fatigue kicked in during the second half and we managed to get a few points on the board.
“For us it’s about getting that hit out before the season starts against Exeter and we want to get as much on the field as possible really.”
Burrell and Saints, who have also beaten Bedford and Moseley during pre-season, now face one final friendly encounter, at Leinster on Friday night, before the big league kick-off.