The Spurs striker turned match-winner when his goal on the hour mark gave Harry Redknapp's side a 1-0 win, as well as another important three points to keep the club's title push on track.
The Baggies defended resolutely throughout Tuesday night's Barclays Premier League encounter, but the predatory instincts of Defoe proved decisive.
"Three points were vital," he told Spurs TV Online. "It was a tough game, in the first half West Brom didn't really attack, they sat in and made it difficult.
"It was important to be patient. We had it a lot last year when teams came here and we dropped a lot of points. But with the winning mentality we've got now, we knew we'd win the game.
"It was just a matter of time before we got the goal, and I was delighted to see it go in. You've just got to be patient and keep creating chances."
The strike marked Defoe's 111th goal for the club, which takes him past Glenn Hoddle on Tottenham's all-time goalscorers list.
"Glenn is a legend at the club," the 29-year-old added. "He played and managed here so it's special for me.
"It only seems like yesterday that I played my first game when I look back, hopefully there are many more goals to come."