But the Samoan wing was honoured to have reached the special milestone at Franklin’s Gardens.
Pisi, who moved to Northampton in 2012, led Saints out at the Gardens for Saturday’s Aviva Premiership game against Wasps.
But it wasn’t to be a happy 100 for the 27-year-old as he had a try disallowed before being yellow carded late on in a 20-15 defeat.
And Pisi said: “I’m a bit gutted, but I’m proud to get my 100 for the Saints.
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“I love the Saints and it’s awesome to run out with my daughter.
“It’s just a shame we didn’t get the win!
“It’s an hour and privilege to play 100 games for the Saints and it is a big achievement for me.”
Saints dominated large periods of the game against Wasps, but eventually they were to suffer a 20-15 defeat, which was their third loss in four league games this season.
And Pisi said: “We’re playing well, it’s just executing when we get down to their end of the field.
“There were a couple of dropped balls, but we’re playing well and we just need to finish things off.
“The bounce of the ball just hasn’t gone our way yet.
“I’m just gutted we couldn’t do it for the fans.”