The ex-Spurs boss comes up against his former employers when his Queens Park Rangers side host Tottenham at Loftus Road on Saturday.
And the 65-year-old admits he has been impressed by the start his successor André Villas-Boas has made to his spell in charge at White Hart Lane.
Redknapp, who took over at QPR in November after being dismissed by Spurs in the summer, believes his former side can mount a genuine title challenge and insists that their squad is far superior to that of their north London rivals.
“I still think they can win the league,” said Redknapp.
“They are a club that can keep improving. I certainly think they’re stronger than Arsenal and there’s not much in it with Chelsea.
“It’s very close now. They’ve got a much better squad than Arsenal.”
Redknapp also praised Villas-Boas for “getting the best” out of Spurs squad, with the Portuguese coach’s side in third place in the Premier League table.
“I couldn’t have done any better than he’s done,” he continued. “He’s done a very good job and he’s got a fantastic squad.
“He’s getting the best out of the players. The team have been fantastic when I’ve seen them. He’s got them playing some great football, as you’d expect him to.”
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