City earned a 2-1 win away to Manchester United last week, having also overcome Arsenal, Chelsea and Liverpool this term, but Redknapp believes that Spurs have the best chance of halting the pacesetters' incredible run.
"Spurs is going to be a big test for Man City," he told talkSPORT. "Tottenham will be their biggest test. If Tottenham are firing on all cylinders, they can certainly give Man City a real game at the weekend.
"But they are all playing for second. There is only going to be one winner now and everybody else is playing for the Champions League positions."
City have failed to win any of their last four meetings with Tottenham, losing three and drawing one since their last victory in May 2015.