Chelsea and Bayern Munich qualified for the last 16 of the Champions League by recording wins to stay perfect in the group stage, and Real Madrid joined them thanks to substitute Sanchez Pedro Leon's last-gasp equalizer in the 2-2 draw at AC Milan on Wednesday.
Filippo Inzaghi's second-half double looked like it would earn Milan victory but Leon's strike deep into second-half injury time means the Spanish giants will definitely finish in the top two in Group G.
The draw means Madrid coach Jose Mourinho, who made his first return to the San Siro since leaving Inter Milan over the summer, is still to lose a game in charge of the nine-time European champions.
Chelsea didn't need such late heroics although it did score all its goals in the second half in the 4-1 win over Spartak Moscow in Group F. Serbia defender Branislav Ivanovic netted twice at Stamford Bridge to add to goals by Nicolas Anelka and Didier Drogba, who converted a penalty.
Bayern was also comfortable winners, Germany striker Mario Gomez hitting a hat trick and Thomas Mueller scoring the fourth in a 4-0 victory at Cluj in Group E.
Arsenal could have also qualified with two games remaining but was defeated 2-1 by Shakhtar Donetsk in Group H, with former Gunners striker Eduardo scoring the winner against his old club. The Croatia international, who didn't celebrate his goal, was also on target against Arsenal two weeks ago.
The most impressive scoreline came at Zilina where Marseille, aided by a hat trick by France striker Andre Pierre Gignac, won 7-0 to record the biggest away victory in Champions League history.
A day after defending champion Inter Milan, Barcelona and Lyon all failed to pick up wins that would have seen them through to the knockout stage, three of the continents other heavyweights showed them how to do it.
Madrid did it the hard way in Wednesday's showcase match at San Siro, a ground where the Spanish league leaders still haven't won in 14 attempts.
"It was a great experience for my team to play at San Siro but it still has to learn how to play Champions League football," Mourinho said. "In the second half, we needed to finish the game off but instead we nearly lost."
After dominating the first half, the visitors deservedly took the lead through Argentina striker Gonzalo Higuain just before the interval but Milan rallied and Inzaghi scored two poacher's goals in the space of 10 minutes.
Leon rescued Madrid with seconds left, collecting a pass in the area and slotting the ball between the legs of Milan goalkeeper Christian Abbiati.
In the group's other match, Auxerre kept alive its slim hope of a top-two finish by beating four-time European champion Ajax 2-1, courtesy of substitute Steven Langil's 84th-minute winner.
Last-place Auxerre has three points in Group G, one less than Ajax and two behind Milan.
Missing injured midfielders Florent Malouda, Michael Essien and Frank Lampard and with captain John Terry on the bench, Chelsea started slowly but found top gear after the break.
Anelka's 49th-minute goal from an acute angle opened the floodgates and Drogba's penalty, which he won himself, was followed by goals by Ivanovic in the 66th and 90th as Chelsea earned a fourth straight win. Substitute Nikita Bazhenov grabbed the consolation for Spartak, which is level on six points with Marseille.
"The first goal was fantastic and it was the most important goal of the evening," Ancelotti said. "He (Anelka) is in the best form of his career."
Didier Deschamps' Marseille team scored at will in Slovakia as Gabriel Heinze, Loic Remy and Lucho Gonzalez joined Gignac in finding the target.
"It's rare to win in the Champions League by such a high score and I'm proud of it," Deschamps said.
Bayern, last season's runner-up, romped to a convincing win at Cluj - its fourth in a row in Group E - to put it six points clear of AS Roma, which won 3-2 at 10-man Basel thanks to goals by Jeremy Menez, Francesco Totti and Leandro Greco. Basel and Cluj are both on three points.
Arsenal went ahead in Donetsk through Theo Walcott's stunning goal on the counterattack but Dmytro Chygrynskiy's goal and Eduardo's sidefooted effort completed the turnaround by Shakhtar, which is now level on nine points with the Gunners.
Braga won 1-0 at Partizan Belgrade to sit three points behind the joint leaders.
