Harry Redknapp has seen Arsenal go from pole position to outsiders in the Premier League title race within the space of two home games, and he expects the task for Arsène Wenger to be even tougher next season.
When West Ham were winning at half-time against Manchester United, the championship looked within Wenger's grasp, but Wayne Rooney staged a comeback for the leaders and Arsenal failed to beat Blackburn later that day.
With the next home game at the Emirates Stadium culminating in a dramatic draw with Liverpool, Redknapp's Tottenham can effectively end their rivals' hopes this evening at White Hart Lane.
Wenger's Invincibles were the last Arsenal team to win the title, in 2004, and Redknapp believes it will be more difficult to finish at the summit next season compared to the current campaign.
"I think its going to be harder," he said. "It's only a matter of time before Manchester City win a championship, that's for sure, if they keep buying top players.
"I think Liverpool will be up there again. I think next year will be harder than this year and this year was harder than the year before."
Should they fail to close the six-point gap on United, this season could be seen as a missed opportunity for Arsenal.
"They had ... Blackburn at home and then they threw away a great opportunity on Sunday and only took a point," Redknapp said. "If they took those extra four points look where they'd be. With Manchester United to play at home still. They would have been in pole position.
"When United drew [Manchester] City in the FA Cup semi-final, they had two legs to play. Chelsea and Arsenal had none of that and you looked at it and I fancied Arsenal strongly at that time.
"They had no distractions. Then suddenly on that Saturday, United came back to win the game and Arsenal couldn't beat Blackburn."
Arsenal have only defeated Leyton Orient and Blackpool since losing in the Carling Cup final in February, leading to questions over whether Wenger can take his team further. But Redknapp has defended his counterpart amid criticism from the influential Arsenal Supporters' Trust.
"I don't understand that at all," Redknapp said. "How can they criticise him? They've had fantastic success and play great football.
"You lose a few games and you have these silly phone-ins, someone calling the radio station saying 'they were rubbish today, absolutely useless'. If people ring up I switch over and put Magic FM on and listen to a bit of music. Why would I want to listen to a bunch of idiots? They must have sad lives with nothing better to do."
Redknapp, however, has seen a change in approach from Wenger. He agreed the pressure has got to the Arsenal manager recently "because he has probably not had it [defeat] so much".
Redknapp added: "We can all sit there with a cigar when you're winning 3-0, saying 'this is good'. Suddenly they started losing and he was one of the biggest nutters of all. He's jumping around more than anyone now. That's how it gets you. We all do it.
"What was he going through when Liverpool got that free-kick on the edge of the box? It's the worst feeling in the world waiting for that free-kick. What he must have gone through on Sunday must not be good for your health, that's for sure."
Meanwhile, the Premier League is not expected to move Stoke City's game against Manchester City following concerns over a conflict of interest regarding European qualification.