The Champions League returns this week - and brings with it a different set of challenges for the Premier League's elite and the champions of Scotland.
Celtic need a good result against Manchester United to keep their hopes alive, but anyone who saw United comprehensively beat Gordon Strachan's side at Old Trafford may think they have a serious problem.
Gordon Strachan's side are always formidable on those fantastic Parkhead nights
Alan Hansen
Do not be taken in by that, because European nights at Parkhead are phenomenal occasions and Celtic's record in front of their own fervent fans is superb, with United actually among their previous victims.
Celtic's away form is their downfall in Europe because there is rarely any bad news for them about playing at home, but they will need to raise their game again on Wednesday.
United will be full of confidence, and despite people looking at their performances against Everton and Hull recently and suggesting they are not quite the team they were last season, this is nonsense.
They have got massive quality up front with Cristiano Ronaldo, Wayne Rooney, Carlos Tevez and Dimitar Berbatov, who now looks to be in a Manchester United mindset and is playing a lot better. This is a real embarrassment of riches for Sir Alex Ferguson.
But Celtic, on their own turf, will be very different from the side beaten so comfortably at Old Trafford and I think they will get a draw.
I am also backing Liverpool to make it through into the knockout stage, when they will again become real contenders for the Champions League.
They face Atletico Madrid at Anfield in a battle of two teams who should reach the last 16, and Rafael Benitez's side will be looking to bounce back from their first defeat of the season at Spurs on Saturday.
I really like the look of Liverpool this season. They should never have lost at White Hart Lane, but the one criticism you have to level at them is that they wasted chances to be out of sight before Spurs got their two goals.
They have played really well in the Champions League and they look more solid than they have done for a very long time. They just look more of a team to me, resilient but with a goal threat.
Benitez has improved the balance of the side, with Albert Riera making a difference on the left and Dirk Kuyt coming into his own on the right, providing crucial goals in both the league and in Europe.
A good team responds well to a setback and the loss at Spurs will test Liverpool, but I am optimistic based on what I have seen from them this season.
Rafael Benitez will wants his side to bounce back against Atletico Madrid
This brings us on to the final two Premier League sides in the Champions League - one which has responded perfectly to a setback and another which needs to prove they can.
Arsenal fall into the latter category after throwing away victory against Spurs at The Emirates and then losing at Stoke City.
The good thing about their game against Fenerbahce is that when you have lost like they did, you want a big game sooner rather than later and they have got one.
The draw against Spurs was the catalyst for what happened at Stoke. The difference in the dressing room mood would have been like a chasm because of the events of the closing minutes against Spurs. Win and you are sky high, draw in those circumstances and it feels like a defeat.
There would have been doom and gloom around training the following day and Stoke would suddenly have felt like a real obstacle. They were never at the races at the Britannia - the body language was not good and they played poorly.
I thought Arsenal played fantastically last season, when they finished third in the league. But it is impossible to see them doing any better this season with effectively the same players.
They need leadership on the field and they need a player in the mould of their former captain Patrick Vieira. They need a player with physical strength who will fit into their system, someone who will get the others going.
Cesc Fabregas is a fantastic talent who would get in my team every time, but he does not have the physical strength of a Steven Gerrard or a Roy Keane or Vieira.
The midfield of Fabregas, Denilson, Samir Nasri and Theo Walcott is very gifted, but it needs some tweaking with the introduction of a physical presence in there.
Arsene Wenger will be looking at this, no doubt, and in the meantime will see the game against Fenerbahce as the perfect opportunity to sweep away any lingering disappointment about the last week.
Chelsea have shown exactly how you come back after a defeat. Eight goals without reply in two games after losing to Liverpool and further evidence of just what an outstanding side they are.
They do not have an easy task away to Roma, but you have to feel they are capable of getting a result anywhere in their current mood and I expect them to do so again.
Alan Hansen was talking to BBC Sport's Phil McNulty
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