Keano drilled a low shot through Sunderland keeper Craig Gordon in injury time to secure a 2-0 win in the Barclays Premier League at the Lane.
He becomes only the 15th player to reach three figures for Spurs and more notably, only the second in the last 20 years to hit the milestone. Teddy Sheringham (1992-97, 2001-03) was the last while before that, it was Glenn Hoddle (1975-87), who left the playing staff over 20 years ago.
"It is a great achievement for him, for Tottenham and the whole Spurs family," said Head Coach Juande afterwards. "It's great for Robbie and I'm very happy for him because this achievement is not easy to reach."
Juande described it as a 'strange' game and it was a match worthy of the old football phrase 'game of two halves'.
We dominated the first period and should have put the issue beyond doubt. Aaron Lennon opened the scoring inside two minutes, Jermaine Jenas went close, Dimitar Berbatov clipped the top of the crossbar and Gordon saved superbly from Jermain Defoe - skipper on the day - and Berbatov.
The second half was a different story though as the Black Cats grew in confidence. Radek Cerny produced a fine late save to deny Liam Miller and also turned away Danny Collins' header while Michael Dawson was there to hack off the line as Kenwyne Jones' header looped towards goal.
Thankfully, the clean sheet stayed intact and Keane made it a day to remember with his century goal.
"The first half was ours and we could have established a two or three-nil lead," added Juande. "There were more opportunities in the second half but these mostly belonged to Sunderland.
"We ended up getting the victory we wanted but we went about it in a rather roundabout way."
There was praise for Cerny as well. "The more he's played the better his form has become and he played a magnificent match."
Aaron Lennon marked his 100th senior appearance in our colours with a goal against Sunderland. Signed from Leeds United during July, 2005, he has scored seven goals in 70 Premier League games for us plus two in 30 cup matches.
Juande Ramos paid tribute to Robbie Keane after the striker clinched victory over Sunderland with his 100th goal for the Club.