The 31-year-old came off the bench to net Spurs' second goal in the 2-0 win over Crystal Palace, adding to Christian Eriksen's opener, but he is set to move to Canada at the end of February having agreed a four-year deal.
Despite suggestions that the switch could damage Defoe's chances of making Roy Hodgson's selection for Brazil, Sherwood believes that he should make the cut irrespective of where he is playing
"Wherever Jermain plays, anywhere in the world, he will score goals," he told Sky Sports. "That's why I would say he's an automatic choice to be on that plane for Brazil.
"You always need goalscorers. I think in this country, we've got good young talents but I'm not sure we've got many better goalscorers than Jermain Defoe."
Speaking of the goal against Palace, Sherwood added: "It was a good finish - typical Jermain.
"That's what he does. It was a bit of a scruffy finish but he's pounced on it and stuck it away in the corner."
Spurs were made to fight for the three points at White Hart Lane, with both goals coming in the second half after Jason Puncheon missed an early penalty for the visitors.
Sherwood praised the resilience of Tony Pulis' Palace side and admitted that they did not resemble relegation candidates based on their first-half showing.
"Crystal Palace didn't look like a team that were struggling at the bottom of the league, they haven't done from the time Tony has been in there and they certainly didn't in the first half," he said.
"I thought they might come and sit but they did the opposite to that, they had threats on the counter attack, they gave us problems and they should have been ahead at half-time.
"They looked like they were playing with a little bit more desire and that's what we talked about at half-time. We've got a group of lads who are very talented but unless you marry the talent with desire, you're going to get found out."
Sherwood was also pleased by Spurs' second-half performance, following an opening 45 minutes which saw Palace cause numerous problems.
"I think in the second half we picked it up and we showed we can match that desire and commitment and then our quality showed," he said.
"We had a period where we could have scored more but we did well second half. I always say it's easier to win games when you start from minute one until the end.
"I've played many games here and in my career where we've had to show character, can you roll your sleeves up? Can you dig in? Can you be brave enough on the ball to go and demand it and take it to the opposition? I think we had that in abundance in the second half."
The result meant that Spurs made it five league games unbeaten, something which Sherwood believes will be key in the second half of the season.
"It's important to get into a run of form of winning and the consistency around that," he said.
"Even though it wasn't going for us at half-time, we believed that we could turn it around and we showed a lot of character to bounce back. We also showed a lot of commitment and ability."