The striker backs the club's January recruits to help them stay up.
The Black Cats currently sit outside the Premier League drop zone in 17th position, but they are far from safe as just one point separates them from Norwich and Newcastle United - who have a game in hand - while bottom-of-the-table Aston Villa are nine off the pace.
Defoe opened the scoring on 85 minutes last Saturday as Sam Allardyce's side looked set for a huge three points away to Southampton, only for the hosts to equalise in the dying stages.
Kone and Khazri - signed from Lorient and Bordeaux in January - have made good first impressions so far, with the latter scoring in the 2-1 win over Manchester United, but Defoe says there is plenty more to come from them in the coming weeks and months.
"I think we will be fine," the 33-year-old, who has netted 11 league goals this season, is quoted as saying by Sky Sports. "I believe from now until the end of the season we will win a few games because of the way we are playing and the players we have got.
"The new signings - Wahbi Khazri, Lamine Kone, all of them, and even the lads that came in during the summer like Younes Kaboul - have lifted us."
Sunderland have the guts of 13 days in which to prepare for their next league outing - a visit to North-East rivals Newcastle in a game which could go a long way toward deciding both sides' Premier League fate.