Barcelona and Milan put one foot in the last 16
Barcelona and AC Milan both enjoyed stress-free home wins in Group H as the two European heavyweights continued their saunter towards the knockout stages.
Andres Iniesta gave Barca a 10th-minute lead against Viktoria Plzen, after being set up by Lionel Messi, who hit an upright either side of half-time. The Czech visitors barely managed a shot in anger and David Villa added a second for Barca eight minutes from time.
Milan went ahead against Bate Borisov in the 33rd minute through Zlatan Ibrahimovic, and Kevin-Prince Boateng doubled the lead on 69 minutes with a thunderbolt from outside the box.
Barca and Milan are both on seven points, with Plzen and Borisov stuck on a point apiece.
In Arsenal's group, Olympiakaos gave themselves a lifeline with a 3-1 home win over Borussia Dortmund -- the Greeks' first points of the campaign.
Jose Holebas gave the hosts the lead early on and, after Robert Lewandowski equalised, Rafik Djebbour put Olympiakos back in front in the 40th minute. Francois Modesto made the game safe 12 minutes from time.
Third-placed Olympiakos are four points behind Arsenal, with Dortmund bottom on one point.
In Chelsea's group, Bayer Leverkusen struck twice in four second-half minutes to overturn Valencia's lead and secure a 2-1 victory.
Jonas Oliveira put the Spaniards ahead midway through the opening period, but the German hosts fought back with goals from Andre Schurrle and Sidney Sam.
Leverkusen stay in second place behind Chelsea on six points, with Valencia four points behind in third.
In Group G, Porto were held to a 1-1 draw by Apoel Nicosia -- Hulk put the Portuguese side ahead on 12 minutes, but Ailton replied six minutes later to keep the Cypriot visitors top of the table on five points, one ahead of Porto and Zenit St Petersburg, who drew 2-2 at Shakhtar Donetsk.