It was the draw that saw Neil Lennon hold his head in his hands as he watched on with his Celtic squad at their Lennoxtown training ground. Now with a trip to Milan less than a fortnight away, the Celtic boss will be using the international break to draw up the master-plan to return to the last-16 of the Champions League.
Barcelona, AC Milan and Ajax are certainly big names in European football, but they are not as strong as they once were - Milan and Ajax especially. And Celtic have a great home record with just two Champions League defeats at Celtic Park from the last 22 matches.
With ten points usually enough to comfortably secure qualification, can Celtic's home form get them close to that figure?
Against Barcelona (0 points?)
Celtic host Barcelona on October 1 and then head to the Camp Nou for a December 11 rematch. Having given the Catalans two tough matches in last season's competition, many have predicted another upset against Lionel Messi and co. That may well be even more unlikely as it was last year given the two impressive recent results - a last minute 2-1 loss away before a 2-1 Celtic Park win.
Those backing Celtic to take points off the Catalans are suggesting that knowing this Barcelona team well after last season's meeting should play into their favour. That, however, is also true from the Barcelona perspective.
While they won't admit it, it is quite possible that Barcelona underestimated Celtic last season. And they paid the price. New boss Gerardo Martino will not let that happen again and the experienced figures in that squad will be keen to stamp out any complacency this time around and make sure that the job gets done.
With Barcelona boasting a stronger squad after Neymar's arrival, while Celtic are arguably weaker following the departures of Gary Hooper and Victor Wanyama, I can't see Celtic taking any points from Barcelona at home or away.
Celtic Park is a tough place to win in European football. Part of the reason for that, however, is the shock factor - most visitors don't expect the noise and passion of the packed stadium to be so great. With Celtic drawing a Barcelona side with that trip fresh in the memory, they will feel very unlucky.
Against AC Milan (3 points?)
This will be Milan's fourth Champions League visit to Celtic Park in the last decade and the Italian side have still not left with a victory.
There were goalless draws in the 2004/05 and 2006/07 competitions and a 2-1 win under Gordon Strachan in the 2007/08 season.
With this AC Milan team a shadow of their former selves, despite the quality they have in Mario Balotelli, Kaká and Stephan El Shaarawy, Celtic will fancy their chances of a home win when Milan visit on November 26.
Milan only just made the Champions League on the last day of last year's Serie A season and had to come through the play-off round like Celtic. They have started this domestic campaign poorly as well with an opening day loss to Verona. This is clearly a Milan team in transition and one which is there for the taking - just like the three points.
As much as Celtic Park is a fortress, however, the San Siro is too. The return legs from the three meetings over the last decade have always seen Celtic lose in Italy and it will be as tricky as ever to take anything from that first group match in Milan on September 18.
Against Ajax (4 points?)
Celtic last met Ajax in Europe in 2001, so it's hard to look at recent history in regards to this tie.
Ajax, however, have had a bad start to the season. Five games is early to judge a team, but there is no other way to put it - Ajax have started poorly.
Two wins, two draws and a loss have left Ajax in fourth place and it's interesting to note that the three matches where points were dropped were all away from the Amsterdam Arena. That doesn't look good for the Dutch champions ahead of their October 22 clash at Celtic Park.
As mentioned earlier, the 'shock factor' of Celtic Park is one of the biggest reasons for Celtic's impressive home record and with Ajax not experiencing that for 12 years, that really will be a factor against the Dutch more so than against Barcelona and Milan.
Ajax's poor start also gives reason to suggest that the away trip to Amsterdam (November 6) could be the best chance to earn a positive away result. To take anything from the Camp Nou or San Siro is a big ask, but bringing a point back from Holland against this team that seems to be struggling since the departures of Christian Eriksen and Toby Alderweield is very possible.
Overall, this Celtic team could well win seven points in this group and should be disappointed if they don't. That's unlikely to be enough, though, and Neil Lennon would have to hope for a big away result to see his side through. Good home results, however, are much more likely and if they can beat Milan and Ajax at Celtic Park then they at least have a chance of making the next round.
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