Defoe has made a habit of scoring in north London over the years - primarily as a Spurs player, when he set a number of records for the side.
The former Tottenham striker is eligible to play against the north London side and he has Lord Sugar worried.
Indeed, the ex-Spurs chairman reckons Defoe is nailed on to net at White Hart Lane.
What's the betting Defoe scores against Spurs tomorrow. Just going to happen you can feel it .— Lord Sugar (@Lord_Sugar) January 16, 2015
Tottenham go into their clash with Sunderland sixth in the Premier League table, with Gus Poyet's side a further 10 places below them in the standings.
Poyet will no doubt hope, though, that the signing of Defoe can change the Black Cats' fortunes.
Sunderland have scored just 18 goals in 21 league games so far this season. But, if Lord Sugar proves correct and Defoe can then build on a promising debut, they could be celebrating more to come in the next few weeks.