AC Milan and Chelsea's Champions League campaign suffered heavy blows when both lost 1-0 on Tuesday while Real Madrid and Lyon scored wins to qualify for the knockout stage.
Chelsea's loss in Seville to Real Betis means they still have unfinished business to ensure their safe passage from Group G.
Substitute Dani Martin's goal left Chelsea manager Jose Mourinho frustrated and his Premiership champions without an away win in Europe for over a year.
The "special one" was apparently incensed by his side's poor performance. "We have nothing to argue with, we have no defence because the performance in the first half was too bad," he said.
"Betis deserved the victory because of their attitude in the first half and how they defended in the second half. We have to look at ourselves, to what didn't work, and try to sort it.
"We are a great team. We weren't a great team tonight but if we are a great team we have to return to our standards," added the Portuguese coach who guided Porto to the Champions League title two years ago.
Chelsea are now lying second on seven points, one ahead of Betis but three adrift of leaders Liverpool after the European champions coasted to a 3-0 win over Anderlecht.
That Anfield result, achieved by goals from Fernando Morientes, Luis Garcia and Djibril Cisse, put Rafael Benitez's men on the brink of qualifying for the knock-out stages.
Nine-time kings of Europe Real Madrid guaranteed their presence in the next phase with a 2-0 win over Rosenborg, an unfortunate own goal by defender Mikael Dorsin and a strike from Guti inflicting the damage on the Norwegians.
Real are in second in group F on nine points, three shy of Lyon who maintained their perfect record with a 4-1 thrashing of Olympiakos in Greece.
The highflying French champions found themselves on the backfoot after Nigerian attacker Haruna Babangida's third minute goal.
But two goals in three minutes just before the break from Juninho and Norwegian striker John Carew set the tone for Gerard Houllier's side, with Malian midfielder Mahamadou Diarra and a second from Carew sealing the tie.
Real and Lyon are now assured of finishing in the first two regardless of how the last two group games pan out.
PSV Eindhoven took control of Group E by avenging last season's semi-final loss to AC Milan with a 1-0 win over the Italian giants at the Philips Stadium.
Their Peruvian striker Jeffersen Farfan bagged the decisive goal in the 12th minute, with Milan reduced to ten men late on after Dutch defender Jaap Stam was sent off for a second rash tackle on American DaMarcus Beasley.
This second win pushed PSV up to seven points, two clear of Schalke 04 who beat bottom-side Fenerbahce, with Milan third on goal difference.
AC's city rivals Inter are on the brink of going through from Group H after a 2-1 win over Porto in Milan.
Two goals in seven minutes from second-half substitute Julio Cruz saw Inter take the honours after Hugo Almedia's long range free-kick found the top corner before the break for Porto.
Source: Xinhua