Liverpool's 4-1 win at Old Trafford on Saturday afternoon has stunned the football world and thrown up all sorts of questions about the title race.
Last week, on a live Sky Sports News debate, former United player Mickey Thomas confidently predicted that United would beat their arch rivals Liverpool and go on to lift the Premier League trophy.
Once the dust had settled, we invited him back to see if he had changed his mind - and we pitted him against former Chelsea favourite Jason Cundy in Monday's Sky Sports News debate.
And while Thomas felt Saturday's defeat was a mere blip in Sir Alex Ferguson's march towards the title, Cundy suggested there is now a chink of light for Liverpool and Chelsea as the pressure mounts on the Red Devils.
Is the title race wide open again?Mickey Thomas: It's a lot tighter, but if we do win our game in hand, that's us seven points ahead of everyone else. I'd rather be in United's position that Liverpool or Chelsea.
They've got to win every game and, of course, United have to drop points. You wouldn't back against United at this stage.
Jason Cundy: Liverpool have done Chelsea and the neutral some favours here because it does leave it open. I wouldn't say it's blown open though. I remember this time last year United went on a bit of a dodgy run, dropping points. Is there more concern at Old Trafford now?
MT: I looked at the table this morning and am still very happy with a four-point lead. I think with the squad we've got we'll respond in the right way. We go to Fulham, we gave them a hiding in the FA Cup, and I'm confident about United's next few fixtures.
Will Saturday's defeat have a mental impact on Manchester United?JC: Possibly. When you look at Sir Alex Ferguson, they've got a manager installed who knows how to win this league. I don't think anyone saw this coming, Mickey certainly didn't, and Liverpool have opened it up slightly. It's too drastic to say they've blown it wide open, but I certainly think this league title race is more interesting than it was.
It could go down to the wire. Of course they're favourites, it's their title to lose, however, Chelsea are in a better position than they were when this weekend started.
MT: It wasn't a great performance from United, but we don't get too many bad days. It's about how you correct it and I'm sure they'll put it to the back of the minds. It was a big disappointment for the fans because the rivalry between these two clubs is enormous, but they're professional and will be focused on the next game. We don't depend on Liverpool or Chelsea to win us the title, we'll do it ourselves.
JC: The fact they didn't come out to the press opens things up in some ways. You talk about mind games and no manager likes facing up to a defeat, but I just wonder whether we can read anything into the fact he didn't come out.
MT: No, you cannot read anything into that. He's been at that club for a long time and there's been some tough situations before. At this time he probably will be hurting, but he knows he's got the confidence and the belief in his squad to go all the way. Yes it'll be tighter, but it's a tough ask to win everything. It's not all doom and gloom like you're trying to make out.
Have Liverpool shown how to beat United? Could this be the start of a real wobble?MT: That's a possibility, bit I don't think it will do.
They've gone and done a job on United and it was very good for them to do that, a fabulous performance. But I do believe it was a bad day at the office for United. We gifted goals - Vidic, who could be footballer of the year - had a bad day and Torres took him to the cleaners on a couple of occasions.
JC: I'd like to think so. Can I see a real wobble? No I can't, I just don't see them falling away and opening the door as much as everyone would like. However, all it takes is one more defeat and the pressure's on.
This is new for Manchester United this season, they've performed so well, but Liverpool have exposed the weaknesses that not many people thought they had. There's some big games coming up and who knows what could happen? Chelsea and Liverpool would need to win all of their games, that's an absolute must. Last year Man United had a little wobble, it opened the door for Chelsea and it went down to the last 45 minutes of the season.
Who will win the title?JC: I still expect Man United to be the side to lift the Premier League, but there's a long way to go and a lot of points to be played. Who knows how they're going to handle the pressure?
MT: Chelsea have got some tough fixtures in their run-in and you're right, they have to win every game and rely on United losing two or three. I don't think it's going to be possible. We've had a blip at the weekend, but we're too good a side to give up this Premier League title.