Chelsea can still win the title, but if you look at their performance against Manchester United then they will have to improve dramatically.
For Gary Neville to put in a performance like he did in a big, high-pressure match was remarkable
The worrying thing for everyone at Chelsea is that they just fell apart under the pressure. When they went behind to Nemanja Vidic's header, their heads went down. It was a very un-Chelsea-like performance.
Over the years, the one thing you could say about Chelsea was that they'd be mentally strong. If they went behind they would grind and they'd never know when they were beaten.
But on Sunday, the team spirit, which has been such a feature for Chelsea, just wasn't there and that would be a worry for manager Luiz Felipe Scolari.
Where does Scolari go from here? Who does he pick in the team? He has got major problems all over the pitch.
The 3-0 defeat at Old Trafford is only one result and Chelsea have some influential players due to return from injury, but the way they've been playing for the last six to eight weeks is a major concern and, in terms of the title race, they're definitely third favourites to win it.
Chelsea need to vary their tactics because against United they played exactly the same way from start to finish.
If you're playing in a game like that you've got to test the opposition by playing it to the front men early - play it short, long, wide.
Chelsea just kept playing six or seven passes in the middle of the park which allowed Manchester Untied to get behind the ball, break Chelsea down quickly and hit them on the break. Chelsea were unable to counteract that.
Scolari's men had some nice possession in the first 30 minutes but they never threatened and, again, that would be another major worry.
A vast majority of these players won back-to-back titles with Jose Mourinho and they're still good enough, but Scolari needs someone like Arjen Robben, someone who has that extra pace and ability.
The big worry for me would be Chelsea's lack of steel - mentally - in certain areas
When Chelsea played with Robben on the left, he wasn't always everybody's favourite but he could go past people, get the ball to the byeline and make defenders turn.
Salomon Kalou and Florent Malouda have been hit and miss and it looks like Didier Drogba and Nicolas Anelka can't play together. Chelsea have also missed Michael Essien's drive, while Deco started the season brightly but has been non-existent lately.
Chelsea still have a squad full of multi-talented players, they just need to be given the right formula and from there the confidence will come back. But the big worry for me would be the lack of steel - mentally - in certain areas.
Manchester United have that great blend of youth and experience and they gave a great performance.
Ryan Giggs and Gary Neville showed incredible hunger and desire for players who have won everything. Ryan, at the age of 35, gave an awesome performance.
Gary Neville had a shocker against Arsenal and it looked, to me, like he might not play again but it just shows that he is amazing professional.
Everyone keeps going on about United's centre-backs, and rightly so, but for Neville to put in a performance like he did in a big, high-pressure match was remarkable. It was a lesson to any footballer about what can be achieved.
United have some hard games this week against Bolton and Wigan. They've got a massive schedule coming up so we'll wait and see what happens, but they've certainly hit a run of form and that display against Chelsea will give the players a lot of confidence.
Benitez and Ferguson engaged each other in a war of words last week
The title race is certainly between Manchester United and Liverpool and it could go either way - the big tests are yet to come.
Liverpool, even though they had a bad performance against Stoke, have done remarkably well, are still strong and have a great chance of winning it.
I thought what manager Rafael Benitez said about United boss Sir Alex Ferguson in his press conference was said in a controlled and structured manner, at times he was funny.
People say it was a rant but there's no way it was a rant. However, as a player you don't want that extra pressure and the pressure is now on Liverpool because of what happened at the weekend.
Benitez would probably have been better off saying 'Alex Ferguson doesn't say anything about teams who finish fourth or fifth so he must think we're his biggest challengers' and let it go, let the players do the talking on the pitch.
Ferguson said what he did to get a reaction and he got a reaction.
If Liverpool had beaten Stoke and Manchester United had drawn against Chelsea everything would now have been forgotten.
Liverpool have to keep on doing what they've been doing. They've only one defeat this season and if they've only been beaten once come the end of the campaign, then they'll win the Premier League.
Alan Hansen was talking to BBC Sport's Aimee Lewis
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