The 30-year-old notched his fifth Europa League goal of the season in a 2-0 win against Anzhi Makhachkala in Russia on Thursday night.
However, Roberto Soldado is expected to be restored to the starting line-up for the London derby against West Ham United at White Hart Lane on Sunday.
And Defoe believes he can ill-afford to be spending time on the sidelines with an England place up for grabs in next summer’s World Cup.
“It is great to score in those competitions but I feel you have got to be scoring in the Premier League,” said Defoe.
“I don’t think at my age I have got anything to prove but to get into the squad that goes to a major tournament, you have got to be playing for your club.
“As you can imagine, it is very frustrating – especially after I worked so hard pre-season and telling people ‘I feel sharper and stronger than ever.’ That has shown in my games.
“I don’t know what more I could do really. I am doing my talking on the pitch.
“Scoring goals is the answer, going out there and showing the manager what I can do.
“Obviously you have a word with the manager. I speak to Andre and stuff like that. But I have got to play, it’s a World Cup year.”
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