Harry Redknapp has proclaimed the end of the Premier League's big four by declaring that only Chelsea and Manchester United are certainties to finish in the Champions League places this season and that the other pair of prized berths for Europe's elite tournament could be filled by any two of several teams – including Tottenham Hotspur.

Liverpool's wobbles so far this season had convinced many observers that one member of the customary top four could be about to surrender their place but after watching his team intensify the pressure on Mark Hughes by trouncing Manchester City 3-0 to end a run of three matches without a win and hoist themselves up to fifth in the table, Redknapp suggested Arsenal may also fall from grace.

"I've said since the start of the season that the champions will come from Chelsea or Manchester United but after that it's up for grabs," he said. "Anything is possible this season. Look at Arsenal, you would have expected them to go up and win at Burnley after beating Liverpool, but they didn't so that shows you how hard it's going to be."

Spurs' chances of fulfilling their pre-season ambitions had been ridiculed after Saturday's home defeat by Wolves, but Redknapp railed against the detractors. "People over-react to one result," he said. "One defeat and you're finished, out of the race. People say 'same old Tottenham, they're going to fall flat on their face.' Players who are great one day are useless the next – it's unbelievable, but that's how the game has gone unfortunately.

"We've been consistent. People go on about no win in three matches but in the draws at Everton and Villa our performances were very good. A lot of teams would be happy with a point away at Everton and Villa. It's possible for us this year, we just have to keep picking up results."

In keeping with his conviction that too much should not be read into one result, Redknapp refused to rule Manchester City out of the battle for the Champions League places, despite the fact that their feeble showing at White Hart Lane meant Hughes's expensively assembled team have won just one of their last 10 league matches. "I certainly wouldn't write them off," said Redknapp. "They're a good team. I expect them to be bang up there."

Whereas Redknapp has been told he must sell some of his peripheral squad members in order to fund any new recruits in January, City have the advantage of being wealthy enough to make offers for any player they want. City's shortcomings last night, however, helped allay any anxiety Redknapp may have felt that superior financial resources could be decisive. For all the money they have pumped in, City have not been able to inject their side with an unquenchable spirit.

"It's about getting the right players," said Redknapp. "Sometimes you can have stars who don't perform. You see the game tonight and you probably think they need … well … they missed [Craig] Bellamy."

The prospect of Hughes being the man to whom any January expenditure is entrusted must have been dented by last night's disjointed performance. The manager, however, ignored any concerns that he may pay for City's unconvincing form with his job, instead declaring that he intends using the January transfer window to address one of the problems that he cannot hide: shambolic defending. "At the moment we are having a bit of difficulty when balls come into our box," said Hughes. "It seems that every opportunity that presents itself to the opposition, they score from."

That is tantamount to an admission that his extravagantly priced central defensive pairing of Joleon Lescott and Kolo Touré has not worked out, though the injury to Lescott, missing last night after undergoing surgery yesterday to repair a floating bone in his knee, and Touré's imminent departure for the African Nations Cup, meant he would probably strengthen anyway. "We're struggling at the back," said Hughes. "We've lost Joleon for six to eight weeks and lose Kolo to the African Nations Cup soon so it's not hard to guess what are as we'll be looking to strengthen."