Spurs are gunning for a top-four finish along with Manchester City and they could halt Chelsea's charge towards a Premier League and FA Cup double with victory over Ancelotti's side.
Tottenham bounced back from last weekend's FA Cup semi-final defeat to Portsmouth with a hard-earned victory over north London rivals Arsenal in midweek. It is that lack of consistency that has prevented Spurs making a title push this season, but Ancelotti has already tipped them to be a real force next term.
"Harry Redknapp is doing a very good job at Tottenham," said the Italian.
"He did a very good job winning the FA Cup in 2008 at Portsmouth.
"Tottenham haven't played with continuity, but have played football with very good quality.
"They are a team that likes to play. They have very good players with a lot of quality. They could challenge next season - they can fight for the title."
Ancelotti promised that Chelsea would take the same attacking mentality to White Hart Lane that saw them defeat Manchester United at Old Trafford.
Chelsea are four points clear of United at the summit and a win would go a long way towards sealing their first title since 2006.
But while United boss Sir Alex Ferguson insists that a draw would be good enough for Chelsea, Ancelotti disagrees.
"I don't think so," added Ancelotti.
"A draw wouldn't be a good result.
"We want to maintain a good philosophy against Tottenham and try to win the game. That would be the best thing. I don't know if it will be possible. I was surprised at their performance against Arsenal because they reacted well after the Portsmouth defeat and played a strong match.
"We want to put pressure on them immediately. I don't know if it's possible because Tottenham will want to do the same. But that is the right way to get a good result."
Ancelotti is boosted by the return of England left-back Ashley Cole, who will be among the Chelsea substitutes.
Cole broke his ankle against Everton on February 10 but has recovered sufficiently to be included in the squad. He had been primed for a return against Stoke on April 25 but he has returned to full fitness even quicker than planned to boost his own chances of earning a place in Fabio Capello's England squad for the World Cup finals this summer.
"Ashley Cole is in the squad," added Ancelotti.
"He's ready, he's fit. He'll start on the bench. I'm not surprised how quickly he's come back. The medical staff have worked very well on him, and he has worked hard. It's good for us to have him fit, and it's good for England as well."