English Premier League giants Liverpool are on the brink of going out of the Champions League after drawing 1-1 with Lyon on Wednesday.
The draw put Lyon through to the knockout stages and they were joined by Sevilla, who were held 1-1 by VfB Stuttgart but assured of a top-two finish in their group when Rangers drew with Unirea Urziceni.
Barcelona's hold on the trophy which they won in such style last season loosened ever so slightly when they were held 0-0 by Russian champions Rubin Kazan.
Indeed Inter Milan's late comeback to gain a 2-1 victory over Dynamo Kiev in Ukraine sees the Italian side go top of the tightest group. Should Barcelona and Kazan finish tied for second place on points it would be the Russian outfit who progress by virtue of their head-to-head record.
Kazan had their chances most notably when their top striker Aleksander Bukharov came on in the second half but found Barcelona goalkeeper Victor Valdes a match for him.
Barcelona coach Josep Guardiola said he never thought it would be easy, especially in temperatures that reached as low as -5 degrees Celsius, but accepted that his side had to get maximum points from their final two matches.
"We looked better in the first half but later in the match Kazan played creative football and could have won," said Guardiola, who guided Barcelona to an unprecedented treble last term.
"The draw is a good result after such a match but now we need to win both of the remaining matches."
His Russian counterpart Kurban Berdyev was more than satisfied.
"We hoped to repeat our performance at Camp Nou (when they won 2-1) and in general we were successful," he said.
"We also created some chances against the world's best club but unfortunately missed them."
Liverpool had bossed the first half against the seven-time French champions with Fernando Torres, Dirk Kuyt and Andriy Voronin all going close.
They looked set to come away with all three points when Ryan Babel struck a stunning opener late on but Lyon broke their hearts when Lisandro Lopez struck with minutes remaining.
Fiorentina's 5-2 romp at home to Debrecen - begun by Adrian Mutu's early goal - has really turned the heat up on Liverpool.
Sevilla didn't have to get out of first gear against Stuttgart and scored a goal in the first half through Jesus Navas after a lovely passing move.
Second place is still up for grabs in their group after Rangers and Unirea Urziceni drew in Bucharest, in a match marred by visiting fans tearing up seats and hurling them onto the pitch.
Arsenal are all but through after a 4-1 victory over Dutch champions AZ Alkmaar.
They did all they had to do for their part in going through, as a brace from Cesc Fabregas and one apiece from Samir Nasri and Abou Diaby saw them to an easy victory, but Standard Liege's 2-0 win over Olympiakos stopped them just short of qualifying.