Like defending champion Barcelona, last year's runner-up, Arsenal, finds its chances of advancing to the knockout phase of the UEFA Champions League compromised after drawing at home on the fourth day of group play.
Coach Arsene Wenger called the Gunners' performance on Wednesday their best ever in Europe, but they could only manage to tie CSKA Moscow, 0-0. The result left Arsenal tied for second place with Porto, a point behind CSKA, with two games to play.
Arsenal will lose any tiebreaker with CSKA — the Russian club won the head-to-head series with its 1-0 victory in the first meeting — and must travel to Oporto for the final game on Dec. 6.
Wenger said Arsenal should have won by as much as 7-0 as Cesc Fabregas, Robin van Persie, Tomas Rosicky and Thierry Henry all wasted golden opportunities.
''I don't think tonight we could be guilty of trying to score the perfect goal — we created clear-cut chances, we dominated this Moscow team by miles,'' he said. ''There was a division's difference between us but we have to take the result.''
Porto beat Hamburg, 3-1, on the road. American Benny Feilhaber made his Champions League debut for HSV, playing all 90 minutes at defensive midfielder.
Elsewhere, Lyon and Real Madrid went through to the last 16 as the Group E representatives, Lyon won its 14th straight game of the season with a 1-0 win over Dynamo Kiev on a goal by 18-year-old striker Karim Benzema in the first half. An own goal gave Real a 1-0 win at Steaua Bucharest.
Manchester United and Celtic still lead Group F despite losses at FC Copenhagen and Benfica, respectively. AC Milan is virtually through from Group H after a 4-1 win over Anderlecht that featured a Kaka hat trick.
SCOREBOARD
Group E
Lyon 1 (Benzema 14) Dynamo Kiev 0.
Real Madrid 1 (own goal 70) Steaua Bucharest 0.
Group F
Benfica 3 (own goal 10, Nuno Gomes 22, Karyaka 76) Celtic 0.
FC Copenhagen 1 (Allbaeck 73) Man. Utd. 0.
Group G
Arsenal 0 CSKA Moscow 0.
Hamburg 1 (van der Vaart 62) Porto 3 (Gonzalez 44, Lopez 61, Moraes 87).
Group H
AC Milan 4 (Kaka 7, 22, 56, Gilardino 88) Anderlecht 1 (Juhasz 61).
AEK Athens 1 (Liberopoulos 74) Lille 0.